Results for "Bing Shen"

total 7825took 0.17s
Subleading power corrections to $B\to γlν$ decay in PQCD approachNov 20 2018Nov 21 2018The leptonic radiative decay $B \to \gamma l\nu$ is of great importance in the determination of $B$ meson wave functions, and evaluating the form factors $ F_{V,A}$ are the essential problem on the study of this channel. We computed next-to-leading power ... More
Broadband imaging with one planar diffractive lensDec 26 2017We demonstrate imaging over the visible band using a single planar diffractive lens. This is enabled via multi-level diffractive optics that is designed to focus over a broad wavelength range, which we refer to as an achromatic diffractive lens (ADL). ... More
Why twisting angles are diverse in graphene Moire patterns?Mar 22 2013Jul 11 2013The interlayer energy of the twisting bilayer graphene is investigated by the molecular mechanics method using both the registry-dependent potential and the Lennard-Jones potential. Both potentials show that the interlayer energy is independent of the ... More
Phonon Modes in Single-Walled Molybdenum Disulphide (MoS2) Nanotubes: Lattice Dynamics Calculation and Molecular Dynamics SimulationJan 03 2014Mar 18 2014We study the phonon modes in single-walled MoS$_{2}$ nanotubes via the lattice dynamics calculation and molecular dynamics simulation. The phonon spectra for tubes of arbitrary chiralities are calculated from the dynamical matrix constructed by the combination ... More
Reversibly tuning the insulating and superconducting state in KxFe2-ySe2 crystals by post-annealingMar 07 2011Since the discovery of superconductivity at 26 K in oxy-pnictide LaFeAsO1-xFx, enormous interests have been stimulated in the field of condensed matter physics and material sciences. Among the many kind of structures in the iron pnictide superconductors, ... More
Long-range adiabatic quantum state transfer through a linear array of quantum dotsJun 28 2012We introduce an adiabatic long-range quantum communication proposal based on a quantum dot array. By adiabatically varying the external gate voltage applied on the system, the quantum information encoded in the electron can be transported from one end ... More
Renormalization group equation improved analysis of $B \to π$ form factors from Light-Cone Sum RulesJul 29 2016Mar 01 2018Within the framework of $B$-meson light-cone sum rules, we compute the one-loop level QCD corrections to $B\to \pi$ transition form factors at small $ q^{2}$ region, in implement of a complete renormalization group equation evolution. To solve the renormalization ... More
Topologically protected interface phonons in two-dimensional nanomaterials: hexagonal boron nitride and silicon carbideDec 05 2017Jul 23 2018We perform both lattice dynamics analysis and molecular dynamics simulations to demonstrate the existence of topologically protected phonon modes in a two-dimensional, monolayer hexagonal boron nitride sheet. The topological phonon modes are found to ... More
Modulation of Thermal Conductivity in Kinked Silicon Nanowires: Phonon Interchanging and Pinching EffectsMar 22 2013We perform molecular dynamics simulations to investigate the reduction of the thermal conductivity by kinks in silicon nanowires. The reduction percentage can be as high as 70% at room temperature. The temperature dependence of the reduction is also calculated. ... More
Fermi surface topology and negative longitudinal magnetoresistance observed in centrosymmetric NbAs2 semimetalFeb 04 2016Mar 14 2016We report transverse and longitudinal magneto-transport properties of NbAs2 single crystals. Attributing to the electron-hole compensation, non-saturating large transverse magnetoresistance reaches up to 8000 at 9 T at 1.8 K with mobility around 1 to ... More
Doping effect of Cu and Ni impurities on the Fe-based superconductor Ba0.6K0.4Fe2As2Apr 16 2013Copper and Nickel impurities have been doped into the iron pnictide superconductor Ba0.6K0.4Fe2As2. Resistivity measurements reveal that Cu and Ni impurities suppress superconducting transition temperature T_c with rates of \Delta T_c/Cu-1% = -3.5 K and ... More
BaFe2Se2O as an Iron-Based Mott Insulator with Antiferromagnetic OrderJun 27 2012Jul 11 2012A new compound with a quasi-two-dimensional array of FeSe3O tetrahedra and an orthorombic structure, namely BaFe2Se2O, has been successfully fabricated. Experimental results show that this compound is an insulator and has an antiferromagnetic (AF) transition ... More
Comparative study of vortex dynamics in CaKFe4As4 and Ba0.6K0.4Fe2As2 single crystalsDec 17 2018We investigate the vortex dynamics in two typical hole doped iron based superconductors CaKFe$_4$As$_4$ (CaK1144) and Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ (BaK122) with similar superconducting transition temperatures. It is found that the magnetization hysteresis ... More
Interlayer Breathing and Shear Modes in Few-Layer Black PhosphorusDec 24 2014The interlayer breathing and shear modes in few-layer black phosphorus are investigated for their symmetry and lattice dynamical properties. The symmetry groups for the even-layer and odd-layer few-layer black phosphorus are utilized to determine the ... More
First principle study of the thermal conductance in graphene nanoribbon with vacancy and substitutional silicon defectAug 30 2011The thermal conductance in graphene nanoribbon with a vacancy or silicon point defect (substitution of C by Si atom) is investigated by non-equilibrium Green's function (NEGF) formalism combined with first-principle calculations density-functional theory ... More
Minimum thermal conductance in graphene and boron nitride superlatticeAug 30 2011The minimum thermal conductance versus supercell size ($d_{s}$) is revealed in graphene and boron nitride superlattice with $d_{s}$ far below the phonon mean free path. The minimum value is reached at a constant ratio of $d_{s}/L\approx 5%$, where $L$ ... More
Molecular dynamics simulation for heat transport in thin diamond nanowiresAug 30 2011The phonon thermal conductivity in diamond nanowires (DNW) is studied by molecular dynamics simulation. It is found that the thermal conductivity in narrower DNW is lower and does not show obvious temperature dependence; a very small value (about 2.0 ... More
Contrasting Pair-Breaking Effects by Doping Mn and Zn in Ba0.5K0.5Fe2As2Jan 07 2010May 05 2010Resistivity, Hall effect, magnetoresistance and DC magnetization were measured in Mn and Zn doped Ba$_{0.5}$K$_{0.5}$Fe$_{2}$As$_{2}$ samples. It is found that the Mn-doping can depress the superconducting transition temperature drastically with a rate ... More
An Ultra-compact Nanophotonic Optical Modulator using Multi-State Topological OptimizationNov 19 2017Optical modulators are one of the most important elements of photonic circuits. Here, we designed, fabricated and characterized a nanophotonic all optical modulator (NOM) in silicon that is an order of magnitude smaller than any previous silicon modulators, ... More
Gamma-Ray Burst/Supernova Associations: Energy partition and the case of a magnetar central engineJun 16 2018Jul 16 2018The favored progenitor model for Gamma-ray Bursts (GRBs) with Supernova (SN) association is the core collapse of massive stars. One possible outcome of such a collapse is a rapidly spinning, strongly magnetized neutron star ("magnetar"). We systematically ... More
QCD calculations of $B \to π, K$ form factors with higher-twist correctionsOct 01 2018We update QCD calculations of $B \to \pi, K$ form factors at large hadronic recoil by including the subleading-power corrections from the higher-twist $B$-meson light-cone distribution amplitudes (LCDAs) up to the twist-six accuracy and the strange-quark ... More
Perturbative corrections to $B \to D$ form factors in QCDJan 24 2017Jun 04 2017We compute perturbative QCD corrections to $B \to D$ form factors at leading power in $\Lambda/m_b$, at large hadronic recoil, from the light-cone sum rules (LCSR) with $B$-meson distribution amplitudes in HQET. QCD factorization for the vacuum-to-$B$-meson ... More
Superconductivity in Ti-doped Iron-Arsenide Compound Sr4Cr0.8Ti1.2O6Fe2As2Apr 06 2009Apr 10 2009Superconductivity was achieved in Ti-doped iron-arsenide compound Sr4Cr0.8Ti1.2O6Fe2As2 (abbreviated as Cr-FeAs-42622). The x-ray diffraction measurement shows that this material has a layered structure with the space group of \emph{P4/nmm}, and with ... More
Vortex images on Ba{1-x}KxFe2As2 observed directly by the magnetic force microscopyDec 12 2011Jan 31 2012The vortex states on optimally doped Ba0.6K0.4Fe2As2 and underdoped Ba0.77K0.23Fe2As2 single crystals are imaged by magnetic force microscopy at various magnetic fields below 100 Oe. Local triangular vortex clusters are observed in optimally doped samples. ... More
Highly anisotropic superconducting gap in underdoped Ba$_{1-x}$K$_x$Fe$_2$As$_2$May 11 2011The in-plane London penetration depth, $\Delta\lambda(T)$, was measured using a tunnel diode resonator in single crystals of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ for five doping levels $x$ ranging from underdoped, $T_c$=11 K ($x$=0.17), to optimally doped, $T_c=$38 ... More
Transport properties and anisotropy of Rb0.8Fe2Se2 single crystalsDec 27 2010May 27 2011Single crystals of Rb{0.8}Fe2Se2 are successfully synthesized with the superconducting transition temperatures T_c{onset}= 31 K and T_c{zero}= 28 K. A clear anomaly of resistivity was observed in the normal state at about 150 K, as found in a similar ... More
Flux dynamics and vortex phase diagram in $Ba(Fe_{1-x}Co_x)_2As_2$ single crystals revealed by magnetization and its relaxationOct 19 2009Oct 21 2009Magnetization and its relaxation have been measured in $Ba(Fe_{1-x}Co_x)_2As_2$ single crystals at various doping levels ranging fromvery underdoped to very overdoped regimes. Sizable magnetization relaxation rate has been observed in all samples, indicating ... More
Exclusive production of $B_c$ mesons in $e^+e^-$ collidersJul 16 2018Within the framework of the perturbative QCD approach, we calculate the time-like $B_cB_c(B_c^*)$ form factors $F(Q^2)$ and $A_2(Q^2)$. We include relativistic corrections and QCD corrections, either of which can give about $20\%$ correction to the leading-order ... More
S wave Kπscattering and effects of κin J/ψ\to {\bar K}^{*0}(892)K^+π^-Sep 06 2005Apr 24 2006$K\pi$ $S$ wave scattering is studied using a chiral unitary approach (ChUT) taking into account coupled channels. With the amplitudes derived from the lowest order chiral Lagrangian as the kernel of a set of coupled channel Bathe-Salpeter equations, ... More
Dynamically generated 0^+ heavy mesons in a heavy chiral unitary approachMar 09 2006Oct 07 2006In terms of the heavy chiral Lagrangian and the unitarized coupled-channel scattering amplitude, interaction between the heavy meson and the light pseudoscalar meson is studied. By looking for the pole of scattering matrix on an appropriate Riemann sheet, ... More
Raman and Infra-red properties and layer dependence of the phonon dispersions in multi-layered grapheneSep 06 2007Apr 10 2008The symmetry group analysis is applied to classify the phonon modes of $N$-stacked graphene layers (NSGL's) with AB- and AA-stacking, particularly their infra-red and Raman properties. The dispersions of various phonon modes are calculated in a multi-layer ... More
Chiral symmetry analysis and rigid rotational invariance for the lattice dynamics of single-wall carbon nanotubesJan 18 2006In this paper, we provide a detailed expression of the vibrational potential for the lattice dynamics of the single-wall carbon nanotubes (SWCNT) satisfying the requirements of the exact rigid translational as well as rotational symmetries, which is a ... More
Adsorbate Migration Effects on Continuous and Discontinuous Temperature-Dependent Transitions in the Quality Factors of Graphene NanoresonatorsAug 19 2013We perform classical molecular dynamics simulation to investigate the mechanisms underpinning the unresolved, experimentally-observed temperature-dependent scaling transition in the quality factors of graphene nanomechanical resonators (GNMR). Our simulations ... More
A lattice dynamical treatment for the total potential energy of single-walled carbon nanotubes and its applications: relaxed equilibrium structure, elastic properties, and vibrational modes of ultra-narrow tubesOct 28 2006Apr 23 2007In this paper, we proposed a lattice dynamic treatment for the total potential energy for single-walled carbon nanotubes (SWCNT's) which is, apart from a parameter for the non-linear effects, extracted from the vibrational energy of the planar graphene ... More
Synthesis, structural and transport properties of the hole-doped Superconductor Pr_{1-x}Sr_xFeAsOOct 06 2008Jan 13 2009Superconductivity was achieved in PrFeAsO by partially substituting Pr^{3+} with Sr^{2+}. The electrical transport properties and structure of this new superconductor Pr_{1-x}Sr_xFeAsO at different doping levels (x = 0.05$\sim$ 0.25) were investigated ... More
Nodeless superconductivity in K$_x$Fe$_{2-y}$Se$_2$ single crystals revealed by low temperature specific heatJan 26 2011Low temperature specific heat (SH) has been measured in K$_x$Fe$_{2-y}$Se$_2$ single crystals with T$_c$ = 32 K. The SH anomaly associated with the superconducting transition is moderate and sharp yielding a value of $\Delta C/T \mid_{T_c}$ = 11.6 $\pm$ ... More
A Knowledge Graph Based Solution for Entity Discovery and Linking in Open-Domain QuestionsDec 05 2018Named entity discovery and linking is the fundamental and core component of question answering. In Question Entity Discovery and Linking (QEDL) problem, traditional methods are challenged because multiple entities in one short question are difficult to ... More
A compact 3.5-dB squeezed light source with atomic ensemblesDec 08 2015Dec 28 2015We reported a compact squeezed light source consisting of an diode laser near resonant on 87Rb optical D1 transition and an warm Rubidium vapor cell. The -4dB vacuum squeezing at 795 nm via nonlinear magneto-optical rotation was observed when applying ... More
Charge-screening role of $c$-axis atomic displacements in YBa$_2$Cu$_3$O$_{6+x}$ and related superconductorsNov 25 2015Feb 16 2016The importance of charge reservoir layers for supplying holes to the CuO$_2$ planes of cuprate superconductors has long been recognized. Less attention has been paid to the screening of the charge transfer by the intervening ionic layers. We address this ... More
Superconductivity induced by doping Pd in SrFe2-xPdxAs2Mar 02 2009Mar 05 2009By using solid state reaction method, we have synthesized the Pd-doped superconductor SrFe2-xPdxAs2. The systematic evolution of the lattice constants indicated that the Fe ions were successfully replaced by the Pd. By increasing the doping content of ... More
High-T_c superconductivity induced by doping rare earth elements into CaFeAsFDec 05 2008We have successfully synthesized the fluoride-arsenide compounds Ca$_{1-x}$RE$_x$FeAsF (RE=Nd, Pr; x=0, 0.6). The x-ray powder diffraction confirmed that the main phases of our samples are Ca$_{1-x}$RE$_x$FeAsF with the ZrCuSiAs structure. By measuring ... More
Summability implies Collet-Eckmann almost surelyNov 16 2011Nov 08 2012We provide a strengthened version of the famous Jakobson's theorem. Consider an interval map $f$ satisfying a summability condition. For a generic one-parameter family $f_t$ of maps with $f_0=f$, we prove that $t=0$ is a Lebesgue density point of the ... More
Abstractive Text Summarization by Incorporating Reader CommentsDec 13 2018In neural abstractive summarization field, conventional sequence-to-sequence based models often suffer from summarizing the wrong aspect of the document with respect to the main aspect. To tackle this problem, we propose the task of reader-aware abstractive ... More
Decay behaviors of Pc hadronic moleculesMar 03 2017Mar 09 2017The $P_c(4380)$ and $P_c(4450)$ states observed recently by LHCb experiment were proposed to be either $\bar{D} \Sigma_c^*$ or $\bar{D}^* \Sigma_c$ S-wave bound states of spin parity $J^P={\frac32}^-$. We analyze the decay behaviors of such two types ... More
Quantum state tomography of a single electron spin in diamond with Wigner reconstructionJul 16 2018We present the experimental reconstruction of the Wigner function of an individual electronic spin qubit associated with a nitrogen-vacancy (NV) center in diamond at room temperature. This spherical Wigner function contains the same information as the ... More
Superconductivity at 15.6 K in Calcium-doped Tb_{1-x}Ca_xFeAsO: the structure requirement for achieving superconductivity in the hole-doped 1111 phaseSep 30 2009Superconductivity at about 15.6 K was achieved in Tb_{1-x}Ca_xFeAsO by partially substituting Tb^{3+} with Ca^{2+} in the nominal doping region x = 0.40 \sim 0.50. A detailed investigation was carried out in a typical sample with doping level of x = 0.44. ... More
Tailoring the Superconductivity and Antiferromagnetic Order in SrFe2-xRhxAs2Mar 05 2009Mar 06 2009By doping Rh to the Fe sites in SrFe2As2, superconductivity is induced when the antiferromagnetic (AF) order is suppressed. The maximum superconducting transition temperature was found at about 22 K with the doping level of x = 0.25. It is found that ... More
Structural and transport properties of Sr2VO{3-delta}FeAs superconductors with different oxygen deficienciesOct 08 2009Oct 09 2009Sr2VO{3-delta}FeAs superconductors with different oxygen deficiencies have been successfully fabricated. It is found that the superconducting transition temperature drops down monotonically with the increase of oxygen deficiency. The diminishing of superconductivity ... More
Transition of stoichiometricSr2VO3FeAs to a superconducting state at 37.2 KApr 10 2009Aug 11 2009The superconductor Sr4V2O6Fe2As2 with transition temperature at 37.2 K has been fabricated. It has a layered structure with the space group of p4/nmm, and with the lattice constants a = 3.9296Aand c = 15.6732A. The observed large diamagnetization signal ... More
(Sr_3Sc_2O_5)Fe_2As_2 as a possible parent compound for FeAs-based superconductorsNov 13 2008Dec 17 2008A new compound with the FeAs-layers, namely (Sr_3Sc_2O_5)Fe_2As_2 (abbreviated as FeAs-32522), was successfully fabricated. It has a layered structure with the space group of I4/mmm, and with the lattice constants a = 4.069 $\AA$ and c = 26.876 $\AA$. ... More
Superconductivity in Fluorine-Arsenide Sr_{1-x}La_xFeAsFOct 14 2008Nov 06 2008Since the discovery of superconductivity\cite{1} at 26 K in oxy-pnictide $LaFeAsO_{1-x}F_x$, enormous interests have been stimulated in the fields of condensed matter physics and material sciences. Among the five different structures in this broad type ... More
Structural stability of lattice-matched heterovalent semiconductor superlatticesSep 27 2013Lattice-matched heterovalent alloys and superlattices have some unique physical properties. For example, their band gap can change by a large amount without significant change in their lattice constants, thus they have great potential for optelectronic ... More
Metastable superconducting state in quenched KxFe2-ySe2Jun 11 2012By direct quenching or post-annealing followed by quenching, we have successfully obtained a series of KxFe2-ySe2 samples with different properties. It is found that the samples directly quenched in the cooling process of growth show superconductivity ... More
Multiple Magnetization Peaks and New Type of Vortex Phase Transitions in Ba0.6K0.4Fe2As2Nov 25 2011Nov 30 2011Magnetization and its relaxation have been measured on Ba0.6K0.4Fe2As2 single crystals with Tc = 39 K. The magnetization hysteresis loops (MHLs) exhibit flux jumps in the low temperature region, and a second peak-effect in the intermediate temperature ... More
Structural distortion and incommensurate noncollinear magnetism in EuAg4As2Sep 19 2018Oct 31 2018Layered pnictide materials have provided a fruitful platform to study various emergent phenomena, including superconductivity, magnetism, charge density waves, etc. Here we report the observation of structural distortion and noncollinear magnetism in ... More
A Review on Flexural Mode of Graphene: Lattice Dynamics, Thermal Conduction, Thermal Expansion, Elasticity, and Nanomechanical ResonanceAug 07 2014Jan 30 2015Single-layer graphene is so flexible that its flexural mode (also called the ZA mode, bending mode, or out-of-plane transverse acoustic mode) is important for its thermal and mechanical properties. Accordingly, this review focuses on exploring the relationship ... More
On Einstein Matsumoto metricsJul 09 2012In this paper, the necessary and sufficient conditions for Matsumoto metrics $F=\frac{\alpha^2}{\alpha-\beta}$ to be Einstein are given. It is shown that if the length of $\beta$ with respect to $\alpha$ is constant, then the Matsumoto metric $F$ is an ... More
Sign-reversal of the in-plane resistivity anisotropy in hole-doped iron pnictidesFeb 20 2012Apr 11 2013The in-plane anisotropy of the electrical resistivity across the coupled orthorhombic and magnetic transitions of the iron pnictides has been extensively studied in the parent and electron-doped compounds. All these studies universally show that the resistivity ... More
Transport properties and asymmetric scattering in Ba$_{1-x}$K$_x$Fe$_2$As$_2$ single crystals compared to the electron doped counterparts Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$}Jun 21 2011Nov 23 2011Resistivity, Hall effect and magnetoresistance have been investigated systematically on single crystals of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ ranging from undoped to optimally doped regions. A systematic evolution of the quasiparticle scattering has been observed. ... More
Study of antiferromagnetic and nematic phase transitions in $BaFe_2(As_{1-x}P_x)_2$ by AC micro-calorimetry and SQUID magnetometryJul 23 2014We study the antiferromagnetic (AFM) and structural phase transitions in single crystal $BaFe_2(As_{1-x}P_x)_2$ $(x=0, 0.3)$ at temperatures $T_N$ and $T_S$, respectively, by high resolution ac microcalorimetry and SQUID magnetometry. The specific heat ... More
Significant change in the electronic behavior associated with structural distortions in the single crystalline SrAg4As2Aug 15 2018Nov 30 2018We report a combined study of transport and thermodynamic measurements on the layered pnictide material SrAg4As2. Upon cooling, a drop in electrical and Hall resistivity, a jump in heat capacity and an increase in susceptibility and magnetoresistance ... More
Transport properties, upper critical field and anisotropy of Ba(Fe$_{0.75}$Ru$_{0.25}$)$_2$As$_2$ single crystalsMar 30 2012The temperature and angle dependent resistivity of Ba(Fe$_{0.75}$Ru$_{0.25}$)$_2$As$_2$ single crystals were measured in magnetic fields up to 14 T. The temperature dependent resistivity with the magnetic field aligned parallel to c-axis and ab-planes ... More
Prompt optical emission and synchrotron self-absorption constraints on emission site of GRBsJun 15 2009Jun 17 2009We constrain the distance of the Gamma-Ray Burst (GRB) prompt emission site from the explosion centre, R, by determining the location of the electron's self absorption frequency in the GRB prompt optical-to-X/gamma-ray spectral energy distribution, assuming ... More
On Einstein Kropina metricsJul 09 2012In this paper, a characteristic condition of Einstein Kropina metrics is given. By the characteristic condition, we prove that a non-Riemannian Kropina metric $F=\frac{\alpha^2}{\beta}$ with constant Killing form $\beta$ on an n-dimensional manifold $M$, ... More
Free-space continuous-variable quantum key distribution of unidimensional Gaussian modulation using polarized coherent-states in urban environmentSep 30 2018We use single homodyne detector to accomplish Continuous-Variable quantum key distribution(CV QKD) in a laboratory and urban environment free-space channel. This is based on Gaussian modulation with coherent-states in the polarization degree of freedom. ... More
Structure and superconductivity of Mg(B1-xCx)2 compoundsMar 09 2001In this paper, we reported the structural properties and superconductivity of Mg(B1-xCx)2 compounds. Powder x-ray diffraction results indicate that the samples crystallize in a hexagonal AlB2-type structure. Due to the chemical activity of Mg powders, ... More
Optical evidence of the chiral magnetic anomaly in Weyl semimetal TaAsOct 12 2018Mar 01 2019Chiral pumping from optical electric fields oscillating at THz frequencies is observed in the Weyl material TaAs with electric and magnetic fields aligned along both the a- and c-axes. Free carrier spectral weight enhancement is measured directly for ... More
Magneto-transport properties of the "hydrogen atom" nodal-line semimetal candidates CaTX (T=Ag, Cd, X=As, Ge)Mar 03 2017Topological semimetals are characterized by protected crossings between conduction and valence bands. These materials have recently attracted significant interest because of the deep connections to high-energy physics, the novel topological surface states, ... More
Close relationship between superconductivity and the bosonic mode in Ba0.6K0.4Fe2As2 and Na(Fe0.975Co0.025)AsOct 30 2013Since the discovery of high temperature superconductivity in the iron pnictides and chalcogenides in early 2008, a central issue has been the microscopic origin of the superconducting pairing. Although previous experiments suggest that the pairing may ... More
Anisotropic resistivity in underdoped single crystals (Ba$_{1-x}$K$_x$)Fe$_2$As$_2$, $0 \leq x<0.35$Jun 02 2011Temperature-dependent in-plane, $\rho_a(T)$, and inter-plane, $\rho_c(T)$, resistivities were measured for the iron-arsenide superconductor (Ba$_{1-x}$K$_x$)Fe $_2$As$_2$ over a broad doping range from parent compound to optimal doping $T_c\approx 38 ... More
Impurity Scattering Effect on Superconductivity and the Violation of Anderson Theorem in Ba(Fe_{1-x}Co_x)_2As_2 Single CrystalsJun 24 2009Jun 30 2009Low-temperature specific heat (SH) and resistivity were measured on Ba(Fe_{1-x}Co_x)_2As_2 single crystals in wide doping region. A sizeable residual specific heat coefficient \gamma_0 was observed in the low temperature limit of all samples. The specific ... More
Superconductivity at 22.3 K in SrFe2-xIrxAs2Feb 23 2009Feb 24 2009By substituting the Fe with the 5d-transition metal Ir in SrFe2As2, we have successfully synthesized the superconductor SrFe2-xIrxAs2 with Tc = 22.3 K at x = 0.5. X-ray diffraction indicates that the material has formed the ThCr2Si2-type structure with ... More
Spectra of Baryons Containing Two Heavy Quarks in Potential ModelOct 07 1999In this work, we employ the effective vertices for interaction between diquarks (scalar or axial-vector) and gluon where the form factors are derived in terms of the B-S equation, to obtain the potential for baryons including a light quark and a heavy ... More
Low Temperature Specific Heat of Optimally Doped BaFe$_{2-x}$$TM_x$As$_{2}$ ($TM$ = Co and Ni) Single Crystals: Constraint on the Pairing GapJun 14 2010Low temperature specific heat has been measured in optimally doped and highly overdoped non-superconducting BaFe$_{2-x}$TM$_x$As$_{2}$ ($TM$ = Co and Ni) single crystals. By using the data of the overdoped samples, we successfully removed the phonon contribution ... More
Vortex creep and critical current densities in superconducting (Ba,K)Fe$_{2}$As$_{2}$ single crystalsJul 07 2012The surprisingly rapid relaxation of the sustainable current density in the critical state of single crystalline Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$ is investigated for magnetic fields oriented parallel to the c-axis and to the $ab$--plane respectively. ... More
Anomalous Meissner effect in pnictide superconductorsOct 22 2010The Meissner effect has been studied in Ba(Fe0.926Co0.074)2As2 and Ba0.6K0.4Fe2As2 single crystals and compared to well known, type-II superconductors LuNi2B2C and V3Si. Whereas flux penetration is mostly determined by the bulk pinning (and, perhaps, ... More
Nontrivial minimal surfaces in a hyperbolic Randers spaceMar 16 2016The contribution of this paper is two-fold. The first one is to derive a simple formula of the mean curvature form for a hypersurface in the Randers space with a Killing field, by considering the Busemann-Hausdorff measure and Holmes-Thompson measure ... More
Magnetic order induces symmetry breaking in the single crystalline orthorhombic CuMnAs semimetalAug 30 2017Recently, orthorhombic CuMnAs has been proposed to be a magnetic material where topological fermions exist around the Fermi level. Here we report the magnetic structure of the orthorhombic Cu0.95MnAs and Cu0.98Mn0.96As single crystals. While Cu0.95MnAs ... More
Coexistence of superconductivity and antiferromagnetism in Ca$_{0.74(1)}$La$_{0.26(1)}$(Fe$_{1-x}$Co$_{x}$)As$_{2}$ single crystalsMar 15 2016We report the transport, thermodynamic, $\mu$SR and neutron study of the Ca$_{0.74(1)}$La$_{0.26(1)}$(Fe$_{1-x}$Co$_{x}$)As$_{2}$ single crystals, mapping out the temperature-doping level phase diagram. Upon Co substitution on the Fe site, the structural/magnetic ... More
Evidence of a spin resonance mode in the iron-based superconductor Ba$_{0.6}$K$_{0.4}$Fe$_{2}$As$_{2}$ from scanning tunneling spectroscopyMay 02 2012We used high-resolution scanning tunneling spectroscopy to study the hole-doped iron pnictide superconductor Ba$_{0.6}$K$_{0.4}$Fe$_{2}$As$_{2}$ ($T_c=38$ K). Features of a bosonic excitation (mode) are observed in the measured quasiparticle density of ... More
Electronic structure and nematic phase transition in superconducting multi-layer FeSe films grown by pulsed laser deposition methodJun 19 2017We report comprehensive angle-resolved photoemission investigations on the electronic structure of single crystal multiple-layer FeSe films grown on CaF2 substrate by pulsed laser deposition (PLD) method. Measurements on FeSe/CaF2 samples with different ... More
Electronic Structure and Superconductivity of FeSe-Related SuperconductorsApr 17 2015Apr 20 2015The FeSe superconductor and its related systems have attracted much attention in the iron-based superconductors owing to their simple crystal structure and peculiar electronic and physical properties. The bulk FeSe superconductor has a superconducting ... More
Spectral Analysis and Identification of Noises in Quantum SystemsNov 22 2012Nov 26 2012In quantum information processing, knowledge of the noise in the system is crucial for high-precision manipulation and tomography of coherent quantum operations. Existing strategies for identifying this noise require the use of additional quantum devices ... More
Superconductivity and phase diagrams in 4d- and 5d-metal-doped iron arsenides SrFe_{2-x}M_xAs_2 (M = Rh, Ir, Pd)Jun 02 2009By substituting the Fe with the 4d and 5d-transition metals Rh, Ir and Pd in SrFe_2As_2, we have successfully synthesized a series of superconductors SrFe_{2-x}M_xAs_2 (M = Rh, Ir and Pd) and explored the phase diagrams of them. The systematic evolution ... More
Colossal Bulk Photovoltaic Effect in a Weyl SemimetalDec 13 2017Oct 17 2018Broadband, efficient and fast conversion of light to electricity is crucial for sensing and clean energy. Here we reveal the largest observed bulk photo-voltaic effect (BPVE), an intrinsic mechanism predicted to be ultrafast and exceed the Shockley-Quiesser ... More
Spectra of Free Diquark in the Bethe-Salpeter ApproachFeb 09 2006In this work, we employ the Bethe-Salpeter (B-S) equation to investigate the spectra of free diquarks and their B-S wave functions. We find that the B-S approach can be consistently applied to study the diqaurks with two heavy quarks or one heavy and ... More
Sign-reversal of the in-plane resistivity anisotropy in iron pnictidesApr 11 2013The concept of an electronically-driven breaking of the rotational symmetry of a crystal, without involving magnetic order, has found experimental support in several systems, from semiconductor heterostructures and ruthenates, to cuprate and iron-pnictide ... More
Observation of Lattice and Andreev Bound States of Vortices in Ba0.6K0.4Fe2As2 Single Crystals with Scanning Tunneling Microscopy/SpectroscopyMay 21 2010For a type-II superconductor, when the applied magnetic field is higher than the lower critical value Hc1, the magnetic flux will penetrate into the superconductor and form quantized vortices, which usually are arranged in an Abrikosov lattice. For the ... More
Uncovering Electron-Phonon Scattering and Phonon Dynamics in Type-I Weyl SemimetalsMar 18 2019Weyl semimetals are 3D phases of matter with topologically protected states that have remarkable macroscopic transport behaviors. As phonon dynamics and electron-phonon scattering play a critical role in the electrical and thermal transport, we pursue ... More
Coexistence of Tunable Weyl Points and Topological Nodal Lines in Ternary Transition-Metal Telluride TaIrTe4Sep 29 2017We report a combined theoretical and experimental study on TaIrTe4, a potential candidate of the minimal model of type-II Weyl semimetals. Unexpectedly, an intriguing node structure with twelve Weyl points and a pair of nodal lines protected by mirror ... More
Competition between superconductivity and magnetic/nematic order as a source of anisotropic superconducting gap in underdoped Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$Jun 09 2014The in-plane London penetration depth, $\Delta\lambda(T)$, was measured using a tunnel diode resonator technique in single crystals of Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$ with doping levels $x$ ranging from heavily underdoped, $x$=0.16 ($T_{c}$=7~K) to ... More
Power Law Like Correlation between Condensation Energy and Superconducting Transition Temperatures in Iron Pnictide/Chalcogenide Superconductors: Beyond the BCS UnderstandingFeb 27 2014Superconducting condensation energy $U_0^{int}$ has been determined by integrating the electronic entropy in various iron pnictide/chalcogenide superconducting systems. It is found that $U_0^{int}\propto T_c^n$ with $n$ = 3 to 4, which is in sharp contrast ... More
A Field-directional Specific Heat Study on the Gap Structure of Overdoped Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$Oct 15 2011Apr 25 2013Low-temperature specific heat is measured on the overdoped Ba(Fe_{1-x}Co_x)_2As_2 (x = 0.13) single crystal under magnetic fields along three different directions. A clear anisotropy is observed on the field dependent electronic specific heat coefficient ... More
Role of multiband effects and electron-hole asymmetry in the superconductivity and normal state properties of Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$Mar 13 2009Oct 17 2009We report a systematic investigation, together with a theoretical analysis, of the resistivity and Hall effect in single crystals of Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$, over a wide doping range. We find a surprisingly great disparity between the relaxation ... More
Programming Requests/Responses with GreatFree in the Cloud EnvironmentFeb 09 2018Programming request with GreatFree is an efficient programming technique to implement distributed polling in the cloud computing environment. GreatFree is a distributed programming environment through which diverse distributed systems can be established ... More
True randomness from an incoherent sourceNov 01 2016Nov 01 2017Quantum random number generators (QRNGs) harness the intrinsic randomness in measurement processes: the measurement outputs are truly random given the input state is a superposition of the eigenstates of the measurement operators. In the case of \emph{trusted} ... More
Trustworthiness of detectors in quantum key distribution with untrusted detectorsOct 14 2014Feb 25 2015Measurement-device-independent quantum key distribution (MDI-QKD) protocol has been demonstrated as a viable solution to detector side-channel attacks. One of the main advantages of MDI-QKD is that the security can be proved without making any assumptions ... More
Entanglement based frequency-time coding quantum key distributionJun 20 2014We extend the prepare-and-measure frequency-time coding quantum key distribution(FT-QKD) protocol to an entanglement based FT-QKD protocol. The latter can be implemented with a correlated frequency measurement scheme based on a time resolving single photon ... More
The local entropy along Ricci flow---Part A: the no-local-collapsing theoremsJun 26 2017We localize the entropy functionals of G. Perelman and generalize his no-local-collapsing theorem and pseudo-locality theorem. Our generalization is technically inspired by further development of Li-Yau estimate along the Ricci flow. It can be used to ... More
Simultaneous classical communication and quantum key distribution using continuous variableJun 08 2016Aug 18 2016Presently, classical optical communication systems employing strong laser pulses and quantum key distribution (QKD) systems working at single-photon levels are very different communication modalities. Dedicated devices are commonly required to implement ... More