Results for "Hai Hu"

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Overview on the physics and materials of the new superconductor KxFe2-ySe2Sep 26 2012Since the discovery of high temperature superconductivity in iron pnictides in early 2008, many iron-based superconductors with different structures have been discovered, with the highest transition temperature to date being 57 K. By the end of 2010, ... More
Vortex-unbinding and finite-size effects in Tl2Ba2CaCu2O8 thin filmsFeb 28 2003Oct 01 2003Current-voltage ($I$-$V$) characteristics of Tl$_2$Ba$_2$CaCu$_2$O$_8$ thin films in zero magnetic field are measured and analyzed with the conventional Kosterlitz-Thouless-Berezinskii (KTB) approach, dynamic scaling approach and finite-size scaling approach, ... 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
A Learning Based Optimal Human Robot Collaboration with Linear Temporal Logic ConstraintsMay 31 2017This paper considers an optimal task allocation problem for human robot collaboration in human robot systems with persistent tasks. Such human robot systems consist of human operators and intelligent robots collaborating with each other to accomplish ... More
Multi-band effect in the noncentrosymmetric superconductors Mg_{12-δ}Ir_{19}B_{16} revealed by Hall effect and magnetoresistance measurementsJun 09 2010We report the longitudinal resistivity and Hall effect measurements on the noncentrosymmetric superconducting Mg$_{12-\delta}$Ir$_{19}$B$_{16}$ samples with different critical transition temperatures. A strong temperature dependence of the Hall coefficient ... More
Two energy scales and close relationship between the pseudogap and superconductivity in underdoped cuprate superconductorsAug 29 2007Sep 29 2007By measuring the low temperature specific heat, the low energy quasi-particle excitation has been derived and analyzed in systematically doped La$_{2-x}$Sr$_{x}$CuO$_{4}$ single crystals. The Volovik's relation predicted for a d-wave superconductor has ... More
Finding the Spectral Radius of a Nonnegative TensorNov 09 2011In this paper, we introduce a new class of nonnegative tensors --- strictly nonnegative tensors. A weakly irreducible nonnegative tensor is a strictly nonnegative tensor but not vice versa. We show that the spectral radius of a strictly nonnegative tensor ... More
Formal residue and computer proofs of combinatorial identitiesSep 20 2011Sep 28 2011The coefficient of x^{-1} of a formal Laurent series f(x) is called the formal residue of f(x). Many combinatorial numbers can be represented by the formal residues of hypergeometric terms. With these representations and the extended Zeilberger's algorithm, ... More
On the structure of $\mathcal{N}_p$-spaces in the ballJul 25 2016We study the structure of $\mathcal{N}_p$-spaces in the ball. In particular, we show that any such space is Moebius-invariant and for $0<p \leq n$, all $\mathcal{N}_p$-spaces are different. Our results will be of important uses in the study of operator ... 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
Spin-orbit coupling and electric-dipole spin resonance in a nanowire double quantum dotMay 15 2018We study the electric-dipole transitions for a single electron in a double quantum dot located in a semiconductor nanowire. Enabled by spin-orbit coupling (SOC), electric-dipole spin resonance (EDSR) for such an electron can be generated via two mechanisms: ... More
Magnetization of potassium doped p-terphenyl and p-quaterphenyl by high pressure synthesisJun 19 2017By using high pressure synthesis method, we have fabricated the potassium doped para-terphenyl. The temperature dependence of magnetization measured in both zero-field-cooled and field-cooled processes shows step like transitions at about 125 K. This ... More
Pressure Induced Superconductivity in the New Compound ScZrCo1-$δ$Oct 11 2017It is widely perceived that the correlation effect may play an important role in several unconventional superconducting families, such as cuprate, iron-based and heavy-fermion superconductors. The application of high pressure can tune the ground state ... More
Too Far to See? Not Really! --- Pedestrian Detection with Scale-aware Localization PolicySep 01 2017A major bottleneck of pedestrian detection lies on the sharp performance deterioration in the presence of small-size pedestrians that are relatively far from the camera. Motivated by the observation that pedestrians of disparate spatial scales exhibit ... 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
Synergy and competition between superconductivity and antiferromagnetism in FeSe under pressureNov 28 2018Temperature dependence of resistivity under high pressures with magnetic fields parallel and perpendicular to the FeSe planes are measured in FeSe single crystals. It is found that the structural transition (nematic) temperature is suppressed by pressure ... More
Pressure induced superconductivity in Bi single crystalsOct 19 2016Measurements on resistivity and magnetic susceptibility have been carried out for Bi single crystals under pressures up to 10.5GPa. The temperature dependent resistivity shows a semimetallic behavior at ambient and low pressures (below about 1.6GPa). ... More
General Logarithmic Corrections to Bekenstein-Hawking EntropySep 20 2006Recently, there has been a lot of attention devoted to resolving the quantum corrections to the Bekenstein-Hawking entropy of the black hole. In particular, the coefficient of the logarithmic term in the black hole entropy correction has been of great ... More
Topological incommensurate magnetization plateaus in quasi-periodic quantum spin chainsSep 13 2014Mar 17 2015Uncovering topologically nontrivial states in nature is an intriguing and important issue in recent years. While most studies are based on the topological band insulators, the topological state in strongly correlated low-dimensional systems has not been ... More
Growth and post-annealing studies of La-Bi2201 single crystalsNov 05 2008Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$ (0$\leq x \leq$1.00) single crystals with high-quality have been grown successfully using the travelling-solvent floating-zone technique. The patterns of X-ray diffraction suggest high crystalline quality of the ... 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
Nodal Superconducting Gap in $β$-FeSDec 13 2015Low temperature specific heat has been measured in superconductor $\beta$-FeS with T$_c$ = 4.55 K. It is found that the low temperature electronic specific heat C$_e$/T can be fitted to a linear relation in the low temperature region, but fails to be ... More
Superconductivity in LiOHFeS single crystals with a shrunk c-axis lattice constantDec 12 2016By using a hydrothermal ion-exchange method, we have successfully grown superconducting crystals of LiOHFeS with ${T_c}$ of about 2.8 K. Being different from the sister sample (Li${_{1-x}}$Fe${_x}$)OHFeSe, the energy dispersion spectrum analysis on LiOHFeS ... More
Highly anisotropic superconducting gaps and possible evidence of antiferromagnetic order in FeSe single crystalsMar 25 2017Specific heat has been measured in FeSe single crystals down to 0.414 K under magnetic fields up to 16 T. A sharp specific heat anomaly at about 8.2 K is observed and is related to the superconducting transition. Another jump of specific heat is observed ... More
The Abel-Zeilberger AlgorithmMay 01 2011We use both Abel's lemma on summation by parts and Zeilberger's algorithm to find recurrence relations for definite summations. The role of Abel's lemma can be extended to the case of linear difference operators with polynomial coefficients. This approach ... More
Strong and nonmonotonic temperature dependence of Hall coefficient in superconducting K$_x$Fe$_{2-y}$Se$_2$ single crystalsJul 06 2014In-plane resistivity, magnetoresistance and Hall effect measurements have been conducted on quenched K$_x$Fe$_{2-y}$Se$_2$ single crystals in order to analysis the normal-state transport properties. It is found that the Kohler's rule is well obeyed below ... 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
Robust superconductivity and transport properties in (Li1-xFex)OHFeSe single crystalsJan 19 2016The recently discovered (Li${_{1-x}}$Fe${_x}$)OHFeSe superconductor with $T_c$ about 40K provides a good platform for investigating the magnetization and electrical transport properties of FeSe-based superconductors. By using a hydrothermal ion-exchange ... More
Fishtail effect and the vortex phase diagram of single crystal Ba0.6K0.4Fe2As2Jul 24 2008Oct 10 2008By measuring the magnetization hysteresis loops of superconducting Ba0.6K0.4Fe2As2 single crystals, we obtained the high upper critical field and large current carrying ability, which point to optimistic applications. The fishtail (or second peak) effect ... More
E-Determinants of TensorsSep 02 2011Sep 13 2011We generalize the concept of the symmetric hyperdeterminants for symmetric tensors to the E-determinants for general tensors. We show that the E-determinant inherits many properties of the determinant of a matrix. These properties include: solvability ... More
Possible nodeless superconductivity in the noncentrosymmetric superconductor Mg_(12-delta)Ir_19B_16Aug 26 2007We measured the resistivity, diamagnetization, and low-temperature specific heat of the newly discovered noncentrosymmetric superconductor Mg_(12-delta)Ir_19B_16. The temperature dependence of specific heat is consistent with the model of an isotropic ... More
Nodeless Superconductivity in the Noncentrosymmetric Superconductor $Mg_{10}Ir_{19}B_{16}$Jun 06 2007Jun 09 2007We measured the resistivity, diamagnetization and low temperature specific heat of the newly discovered noncentrosymmetric superconductor $Mg_{10}Ir_{19}B_{16}$. It is found that the superconducting gap has an s-wave symmetry with a value of about $\Delta_0 ... More
Vortex lattice and vortex bound states in CsFe$_2$As$_2$ investigated by scanning tunneling microscopy/spectroscopyJan 08 2018Jul 11 2018We investigate the vortex lattice and vortex bound states in CsFe$_2$As$_2$ single crystals by scanning tunneling microscopy/spectroscopy (STM/STS) under various magnetic fields. A possible structural transition or crossover of vortex lattice is observed ... More
Unprecedented High Irreversibility Line in Nontoxic Cuprate Superconductor (Cu,C)Ba2Ca3Cu4O11+deltaMay 15 2018One of the key factors limiting the high power applications for a type-II superconductor is the irreversibility line Hirr(T) which reflects the very boundary of resistive dissipation in the phase diagram of magnetic field versus temperature. In cuprate ... More
Far-field nanoscale infrared spectroscopy of vibrational fingerprints of molecules with graphene plasmonsJun 30 2016Infrared spectroscopy, especially for molecular vibrations in the fingerprint region between 600 and 1500 cm-1, is a powerful characterization method for bulk materials. However, molecular fingerprinting at the nanoscale level still remains a significant ... More
Strong coupling superconductivity revealed by scanning tunneling microscope in tetragonal FeSMay 17 2016Jul 27 2016We investigate the electronic properties of the tetragonal FeS superconductor by using scanning tunneling microscope/spectroscopy. It is found that the typical tunneling spectrum on the top layer of sulfur can be nicely fitted with an anisotropic s-wave ... More
Upper critical field and quantum oscillations in tetragonal superconducting FeSAug 03 2016Sep 26 2016The magnetoresistance and magnetic torque of FeS are measured in magnetic fields $B$ of up to 18 T down to a temperature of 0.03 K. The superconducting transition temperature is found to be $T_c$ = 4.1 K, and the anisotropy ratio of the upper critical ... More
Multi-band superconductivity and large anisotropy in FeS crystalsNov 27 2015Feb 19 2016By using a hydrothermal method, we have successfully grown crystals of the newly discovered superconductor FeS, which has an isostructure of the iron based superconductor FeSe. The superconductivity appears at about 4.5K, as revealed by both resistive ... More
Scrutinizing the double superconducting gaps and strong coupling pairing in (Li1-xFexOH)FeSeJun 15 2015Aug 05 2015In the iron based superconductors, one of the on-going frontier studies is about the pairing mechanism. The recent interest concerns the high temperature superconductivity and its intimate reason in the monolayer FeSe thin films. The challenge here is ... More
Structures and Physical Properties of CsV$_2$Se$_{2-x}$O and V$_2$Se$_2$OMar 02 2018By using solid-state reactions, we successfully synthesize new oxyselenides CsV$_2$Se$_{2-x}$O (x = 0, 0.5). These compounds containing V$_2$O planar layers with a square lattice crystallize in the CeCr$_2$Si$_2$C structure with the space group of $P4/mmm$. ... More
Possible superconducting fluctuation and pseudogap state above $T_c$ in CsFe$_2$As$_2$Apr 25 2016Resistive, magnetization, torque, specific heat and scanning tunneling microscopy measurements are carried out on the hole heavily doped CsFe$_2$As$_2$ single crystals. A characteristic temperature $T^*\sim13$ K, which is several times higher than the ... More
Rigid vortices in MgB2Mar 21 2003Oct 01 2003Magnetic relaxation of high-pressure synthesized MgB$_2$ bulks with different thickness is investigated. It is found that the superconducting dia-magnetic moment depends on time in a logarithmic way; the flux-creep activation energy decreases linearly ... More
Sign reversal superconducting gaps revealed by phase referenced quasi-particle interference of impurity induced bound states in (Li$_{1-x}$Fe$_x$)OHFe$_{1-y}$Zn$_y$SeMar 28 2018By measuring the spatial distribution of differential conductance near impurities on Fe sites, we have obtained the quasi-particle interference (QPI) patterns in the (Li$_{1-x}$Fe$_x$)OHFe$_{1-y}$Zn$_y$Se superconductor with only electron Fermi surfaces. ... More
Universality and unconventional enhancement of flux-flow resistivity in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$Dec 06 2016Measurements of the current-voltage characteristics were performed on Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystals with doping level $0.044 \leq x \leq 0.1$. An unconventional increase in the flux-flow resistivity $\rho_{\rm ff}$ with decreasing magnetic ... More
Superconductivity with two-fold symmetry in topological superconductor SrxBi2Se3Jul 21 2016Topological superconductivity is the quantum condensate of paired electrons with an odd parity of the pairing function. One of the candidates is the triplet pairing superconductor derived from topological insulator Bi2Se3 by chemical doping. Theoretically ... 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
LEASGD: an Efficient and Privacy-Preserving Decentralized Algorithm for Distributed LearningNov 27 2018Distributed learning systems have enabled training large-scale models over large amount of data in significantly shorter time. In this paper, we focus on decentralized distributed deep learning systems and aim to achieve differential privacy with good ... More
The Principle of Navigation Constellation Composed of SIGSO Communication SatellitesNov 23 2012The Chinese Area Positioning System (CAPS), a navigation system based on GEO communication satellites, was developed in 2002 by astronomers at Chinese Academy of Sciences. Extensive positioning experiments of CAPS have been performed since 2005. On the ... More
Nodal Gap in Fe-Based Layered Superconductor LaO_0.9F_{0.1-delta}FeAs Probed by Specific Heat MeasurementsMar 06 2008Mar 07 2008We report the specific heat measurements on the newly discovered Fe-based layered superconductor LaO_0.9F_{0.1-delta}FeAs with the onset transition temperature T_c \approx 28 K. A nonlinear magnetic field dependence of the electronic specific heat coefficient ... More
Partially unstable attractors in networks of forced integrate-and-fire oscillatorsApr 13 2017The asymptotic attractors of a nonlinear dynamical system play a key role in the long-term physically observable behaviors of the system. The study of attractors and the search for distinct types of attractor have been a central task in nonlinear dynamics. ... More
A discussion on vacuum polarization correction to the cross-section of $e^+e^-\toγ^\ast/ψ\toμ^+μ^-$May 10 2018Dec 16 2018Vacuum polarization is a part of the initial-state radiative correction for the cross-section of $e^+e^-$ annihilation processes. In the energy region in the vicinity of narrow resonances $J/\psi$ and $\psi(3686)$, the vacuum polarization contribution ... More
Pressure Induced Enhancement of Superconductivity in LaRu2P2Apr 14 2015To explore new superconductors beyond the copper-based and iron-based systems is very important. The Ru element locates just below the Fe in the periodic table and behaves like the Fe in many ways. One of the common thread to induce high temperature superconductivity ... More
Region-Based Rate-Control for H.264/AVC for Low Bit-Rate ApplicationsFeb 28 2015Rate-control plays an important role in video coding. However, in the conventional rate-control algorithms, the number and position of Macroblocks (MBs) inside one basic unit for rate-control is inflexible and predetermined. The different characteristics ... More
LineNet: a Zoomable CNN for Crowdsourced High Definition Maps Modeling in Urban EnvironmentsJul 16 2018High Definition (HD) maps play an important role in modern traffic scenes. However, the development of HD maps coverage grows slowly because of the cost limitation. To efficiently model HD maps, we proposed a convolutional neural network with a novel ... More
Three-dimensional numerical study of flow characteristic and membrane fouling evolution in an enzymatic membrane reactorJan 02 2018In order to enhance the understanding of membrane fouling mechanism, the hydrodynamics of granular flow in a stirred enzymatic membrane reactor was numerically investigated in the present study. A three-dimensional Euler-Euler model, coupled with k-e ... More
Discovery of a new nontoxic cuprate superconducting system Ga-Ba-Ca-Cu-OMay 23 2018Superconductivity is observed in a new nontoxic cuprate system Ga-Ba-Ca-Cu-O, with Tc = 82K for GaBa2Ca5Cu6O14+{\delta} (Ga-1256) and Tc = 116K probably for GaBa2Ca3Cu4O10+{\delta} (Ga-1234) or GaBa2Ca2Cu3O8+{\delta} (Ga-1223), respectively. All compounds ... 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
The formation of boron sheet at the Ag(111) surface: From clusters, ribbons, to monolayersJan 07 2016Boron (B) sheet has been intently studied and various candidates with vacancies have been proposed by theoretical investigations, including the possible growth on metal surface. However, a recent experiment (Science 350, 1513, 2015) reported that the ... More
Superconductivity induced by doping Platinum in BaFe2As2Jan 27 2010Apr 01 2010By substituting Fe with the 5d-transition metal Pt in BaFe2As2, we have successfully synthesized the superconductors BaFe2-xPtxAs2. The systematic evolution of the lattice constants indicates that the Fe ions were successfully replaced by Pt ions. By ... More
Point-Contact Spectroscopy of Iron-Based Layered Superconductor LaO$_{0.9}$F$_{0.1-δ}$FeAsMar 17 2008Aug 07 2008We present point-contact spectroscopy data for junctions between a normal metal and the newly discovered F-doped superconductor LaO$_{0.9}$F$_{0.1-\delta}$FeAs (F-LaOFeAs). A zero-bias conductance peak was observed and its shape and magnitude suggests ... More
Collective vortex pinning and crossover between second order to first order transition in optimally doped Ba1-xKxBiO3 single crystalsJan 05 2017Measurements on magnetization and relaxation have been carried out on an optimally doped Ba$_{0.59}$K$_{0.47}$BiO$_{3+\delta}$ single crystal with $T_c$ = 31.3 K. Detailed analysis is undertaken on the data. Both the dynamical relaxation and conventional ... More
Multi-Band Exotic Superconductivity in the New Superconductor Bi4O4S3Jul 20 2012Resistivity, Hall effect and magnetization have been investigated on the new superconductor Bi4O4S3. A weak insulating behavior has been induced in the normal state when the superconductivity is suppressed. Hall effect measurements illustrate clearly ... More
Pressure Tuned Enhancement of Superconductivity and Change of Ground State Properties in LaO0.5F0.5BiSe2 Single CrystalsJul 22 2014By using a hydrostatic pressure, we have successfully tuned the ground state and superconductivity in LaO0.5F0.5BiSe2 single crystals. It is found that, with the increase of pressure, the original superconducting phase with Tc about 3.5 K can be tuned ... More
Intrinsic Josephson junctions in the iron-based multi-band superconductor (V2Sr4O6)Fe2As2May 22 2014In layered superconductors, Josephson junctions may be formed within the unit cell due to sufficiently low interlayer coupling. These intrinsic Josephson junction (iJJ) systems have attracted considerable interest for their application potential in quantum ... More
Magnetism and superconductivity in Sr$_2$VFeAsO$_3$ revealed by $^{75}$As- and $^{51}$V-NMR under elevated pressuresMay 13 2014We report $^{75}$As- and $^{51}$V-nuclear magnetic resonance (NMR) measurements on the iron-based superconductor Sr$_2$VFeAsO$_3$ with alternating stacks structure. We find that the $^{75}$As nuclear spin-spin relaxation rate ($1/T_2$) shows a pronounced ... More
Upper critical field, Hall effect and magnetoresistance in the iron-based layered superconductor LaFeAsO_{0.9}F_{0.1-δ}Mar 09 2008Jul 22 2008By using a two-step method, we successfully synthesized the iron based new superconductor LaFeAsO_{0.9}F_{0.1-\delta}$. The resistive transition curves under different magnetic fields were measured, leading to the determination of the upper critical field ... More
Upper critical field, anisotropy, and superconducting properties of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ single crystalsAug 18 2008Oct 06 2008The temperature dependent resistivity of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ (x = 0.23, 0.25, 0.28 and 0.4) single crystals and the angle dependent resistivity of superconducting Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ single crystals were measured in magnetic fields ... More
Growth and characterization of A_{1-x}K_xFe_2As_2 (A = Ba, Sr) single crystals with x=0 - 0.4Jul 05 2008Oct 18 2008Single crystals of A$_{1-x}$K$_x$Fe$_2$As$_2$ (A=Ba, Sr) with high quality have been grown successfully by FeAs self-flux method. The samples have sizes up to 4 mm with flat and shiny surfaces. The X-ray diffraction patterns suggest that they have high ... More
Hall effect and magnetoresistance in single crystals of NdFeAsO$_{1-x}$F$_{x}$Jun 10 2008Sep 09 2008Hall effect and magnetoresistance have been measured on single crystals of $NdFeAsO_{1-x}F_{x}$ with x = 0 ($T_c$ = 0 $ $K) and x = 0.18 ($T_c$ = 50 $ $K). For the undoped samples, strong Hall effect and magnetoresistance with strong temperature dependence ... More
Synthesizing and characterization of hole doped nickel based layer superconductor (La$_{1-x}$Sr$_{x}$)ONiAsMar 27 2008Mar 29 2008We report the synthesizing and characterization of the hole doped Ni-based superconductor ($La_{1-x}Sr_{x})ONiAs$. By substituting La with Sr, the superconducting transition temperature $T_c$ is increased from 2.75 K of the parent phase $LaONiAs$ to 3.7 ... More
BCS-like critical fluctuations with limited overlap of Cooper pairs in FeSeApr 28 2017Jul 14 2017In conventional superconductors, very narrow superconducting fluctuation regions are observed above $T_c$ because of the strong overlapping of Cooper pairs in a coherence volume. In the bulk form of iron chalcogenide superconductor FeSe, it is argued ... More
Non-Markovian full counting statistics in quantum dot moleculesFeb 11 2015Full counting statistics of electron transport is a powerful diagnostic tool for probing the nature of quantum transport beyond what is obtainable from the average current or conductance measurement alone. In particular, the non-Markovian dynamics of ... More
An Evidence of Mass Dependent Differential Kinetic Freeze-out Scenario Observed in Pb-Pb Collisions at 2.76 TeVJan 01 2016Jul 07 2016Transverse momentum spectra of different particles produced in mid-rapidity interval in lead-lead (Pb-Pb) collisions with different centrality intervals, measured by the ALICE Collaboration at center-of-mass energy per nucleon pair $\sqrt{s_{NN}}=2.76$ ... More
Kinetic freeze-out temperatures in central and peripheral collisions: Which one is larger?Mar 15 2017Feb 19 2018The kinetic freeze-out temperatures, $T_0$, in nucleus-nucleus collisions at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies are extracted by four methods: i) the Blast-Wave model with Boltzmann-Gibbs statistics (the ... More
Examining the model dependence of the determination of kinetic freeze-out temperature and transverse flow velocity in small collision systemAug 24 2017Sep 06 2018The transverse momentum distributions of the identified particles produced in small collision systems at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) have been analyzed by four models. The first two models utilize the blast-wave ... More
Automatic Article Commenting: the Task and DatasetMay 09 2018May 11 2018Comments of online articles provide extended views and improve user engagement. Automatically making comments thus become a valuable functionality for online forums, intelligent chatbots, etc. This paper proposes the new task of automatic article commenting, ... 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
Discrete energy levels of Caroli-de Gennes-Martricon states in quantum limit due to small Fermi energy in FeTe$_{0.55}$Se$_{0.45}$Sep 27 2017Caroli-de Gennes-Martricon (CdGM) states were predicted in 1964 as low energy excitations within vortex cores of type-II superconductors. In the quantum limit, namely $T/T_\mathrm{c} \ll \Delta/E_\mathrm{F}$, the energy levels of these states were predicted ... More
Doping Dependence of Superconductivity and Lattice Constants in Hole Doped $La_{1-x}Sr_xFeAsO$Jun 12 2008Jun 12 2008By using solid state reaction method we have fabricated the hole doped $La_{1-x}Sr_xFeAsO$ superconductors with Sr content up to 0.13. It is found that the sharp anomaly at about 150 K and the low temperature upturn of resistivity are suppressed by doping ... More
Hall effect and magnetoresistance in the normal state of the superconductor LaO$_{0.9}$F$_{0.1-x}$FeAsMar 05 2008Mar 28 2008By using a two-step method, we successfully synthesized the iron based new superconductor LaO$_{0.9}$F$_{0.1-x}$FeAs. The Hall effect and magnetoresistance were measured in wide temperature region. A negative Hall coefficient R_H has been found implying ... More
Nodal Superconductivity with Multiple Gaps in SmFeAsO$_{0.9}$F$_{0.1}$Jun 12 2008Aug 07 2008We report the observation of two gaps in the superconductor SmFeAsO$_{0.9}$F$_{0.1}$ (F-SmFeAsO) with $T_c=51.5K$ as measured by point-contact spectroscopy. Both gaps decrease with temperature and vanish at $T_c$ and the temperature dependence of the ... More
Inherent Relation between Nernst Signal and Nodal Quasiparticle Transport in Pseudogap Region of Underdoped High Temperature SuperconductorsOct 01 2004Oct 03 2004In-plane Nernst signal and resistivity have been measured for three $La_{2-x}Sr_xCuO_4$ single crystals (x=0.09, 0.11 and 0.145) with the magnetic field parallel to c-axis. A quadratic temperature dependence of resistivity, i.e., $\rho=\rho_0+aT^2$ is ... More
Impurity effect and suppression to superconductivity in Na(Fe$_{0.97-x}$Co$_{0.03}$T$_x$)As (T=Cu, Mn)Aug 06 2013We report the successful growth and the impurity scattering effect of single crystals of Na(Fe$_{0.97-x}$Co$_{0.03}$T$_x$)As (T=Cu, Mn). The temperature dependence of DC magnetization at high magnetic fields is measured for different concentrations of ... More
Superconductivity Appears in the Vicinity of an Insulating-Like Behavior in CeO$_{1-x}$F$_{x}$BiS$_{2}$Aug 24 2012Resistive and magnetization properties have been measured in BiS$_2$-based samples CeO$_{1-x}$F$_{x}$BiS$_{2}$ with a systematic substitution of O with F (0 $<$ x $<$ 0.6). In contrast to the band structure calculations, it is found that the parent phase ... 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
Adversarial Connective-exploiting Networks for Implicit Discourse Relation ClassificationApr 01 2017Implicit discourse relation classification is of great challenge due to the lack of connectives as strong linguistic cues, which motivates the use of annotated implicit connectives to improve the recognition. We propose a feature imitation framework in ... More
Direct Evidence of Superconductivity with Twofold Symmetry in Bi2Te3 Thin Film Deposited on FeTe0.55Se0.45Apr 25 2018Topological superconductor is a timely and frontier topic in condensed matter physics. In superconducting state, an order parameter will be established with the basic or subsidiary symmetry of the crystalline lattice. In doped Bi2Se3 with a basic threefold ... More
Simultaneous Vanishing of the Nematic Electronic State and the Structural Orthorhombicity in NaFe$_{1-x}$Co$_x$As Single CrystalsNov 04 2014We have carried out in-plane resistivity measurements under a uniaxial pressure in NaFe$_{1-x}$Co$_x$As single crystals. A clear distinction of the in-plane resistivity $\rho_a$ and $\rho_b$ with the uniaxial pressure along $b$-axis was discovered in ... More