Latest in cond-mat.supr-con

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Achievement of FCC specification in critical current density for Nb3Sn superconductors with artificial pinning centersMar 19 2019In this letter we demonstrate achievement of record non-Cu critical current density (Jc,non-Cu) in ternary, multifilamentary Nb3Sn conductors by the introduction of artificial pinning centers (APC). In the past two years, we have made great progress in ... More
Spacing Dependent and Doping Independent Superconductivity in Intercalated 1T Two Dimensional SnSe2Mar 19 2019The weak van der Waals interlayer interactions in the transition metal dichalcogenide (TMD) materials have created a rich platform to study their exotic electronic properties through chemical doping or physical gating techniques. We reported bulk superconductivity ... More
First performance test of 30 mm iron-based superconductor single pancake coil under 24 T background fieldMar 19 2019The iron-based superconductor (IBS) single pancake coil (SPC) with 30 mm inner diameter was firstly fabricated and tested under 24 T background field. This SPC was successfully made using the 7-filamentary Ba1-xKxFe2As2 (Ba122) tape by wind-and-react ... More
Discovery of High Dimensional Band Topology in Twisted Bilayer GrapheneMar 19 2019Recently twisted bilayer graphene(t-BLG) emerges as a new strongly correlated physical platform near a magic twist angle, which hosts many exciting phenomena such as the Mott-like insulating and unconventional superconducting behavior. Besides the apparent ... More
Pressure-induced superconductivity in layered pnictogen diselenide NdO0.8F0.2Sb1-xBixSe2 (x = 0.3 and 0.7)Mar 19 2019Polycrystalline samples of layered pnictogen diselenide NdO0.8F0.2Sb1-xBixSe2 (x = 0 to 0.8) were successfully synthesized by solid-state reactions. Electrical resistivity in the synthesized samples was systematically decreased with an increase in Bi ... More
Grooved Dayem nanobridges as building blocks of high-performance YBa$_2$Cu$_3$O$_{7-δ}$ SQUID magnetometersMar 18 2019We present noise measurements performed on a YBa$_2$Cu$_3$O$_{7-\delta}$ nanoscale weak-link-based magnetometer consisting of a Superconducting QUantum Interference Device (SQUID) galvanically coupled to a $3.5 \times 3.5~$mm$^2$ pick-up loop, reaching ... More
Observation of superconductivity with Tc onset at 12K in electrically tunable twisted double bilayer grapheneMar 16 2019Electron-electron interactions play an important role in graphene and related systems to induce exotic quantum states, especially in a stacked bilayer with a small twist angle. Under a magic twist angle in a bilayer graphene, flat band and strong many-body ... More
Determination of effective Cooper pair mass by electrostatic doping of fluxoids of superconductor surface. TheoryMar 16 2019We propose an experimental setup for the determination of the effective Cooper pair mass $m^{*}$ by electrostatic doping of Abrikosov vortices of a superconductor surface. To that end, a superconductor is placed in a constant external magnetic field, ... More
Interfacial superconductivity induced by single-quintuple-layer Bi$_2$Te$_3$ on top of FeTe forming van-der-Waals heterostructureMar 15 2019We report the first clear observation of interfacial superconductivity on top of FeTe(FT) covered by one quintuple-layer Bi$_2$Te$_3$(BT) forming van-der-Waals heterojunction. Both transport and scanning tunneling spectroscopy measurements confirm the ... More
Band-selective clean- and dirty-limit superconductivity with nodeless gaps in the bilayer iron-based superconductor CsCa$_2$Fe$_4$As$_4$F$_2$Mar 15 2019The optical properties of the new iron-based superconductor CsCa$_2$Fe$_4$As$_4$F$_2$ with $T_c \sim 29$~K have been determined. In the normal state a good description of the low-frequency response is obtained with a superposition of two Drude components ... More
Time reversal symmetry breaking superconductorsMar 15 2019The paper reviews recent work on time reversal symmetry (TRS) breaking superconductors. The family of TRS breaking superconductors is growing relatively fast, with many of its newly discovered members being non-centrosymmetric. However, many of the superconductors ... More
Demonstration of nonstoquastic Hamiltonian in coupled superconducting flux qubitsMar 14 2019Quantum annealing (QA) is a heuristic algorithm for finding low-energy configurations of a system, with applications in optimization, machine learning, and quantum simulation. Up to now, all implementations of QA have been limited to qubits coupled via ... More
Demonstration of nonstoquastic Hamiltonian in coupled superconducting flux qubitsMar 14 2019Mar 15 2019Quantum annealing (QA) is a heuristic algorithm for finding low-energy configurations of a system, with applications in optimization, machine learning, and quantum simulation. Up to now, all implementations of QA have been limited to qubits coupled via ... More
Observation of topological transition in high-T$_{c}$ superconductor FeTe$_{1-x}$Se$_{x}$/SrTiO$_{3}$(001) monolayersMar 14 2019Superconductors with topological surface or edge states have been intensively explored for the prospect of realizing Majorana bound states, which obey non-Abelian statistics and are crucial for topological quantum computation. The traditional routes for ... More
Quasiparticle Interference and Symmetry of Superconducting Order Parameter in Strongly Electron-Doped Iron-based SuperconductorsMar 14 2019Motivated by recent experimental reports of significant spin-orbit coupling (SOC) and a sign-changing order-parameter in the Li$_{1-x}$Fe$_x$(OHFe)$_{1-y}$Zn$_y$Se superconductor with only electron pockets present, we study the possible Cooper-pairing ... More
SO(4) FLEX+DMFT formalism with SU(2)$\otimes$SU(2)-symmetric impurity solver for superconductivity in the repulsive Hubbard modelMar 14 2019Here we have developed a FLEX+DMFT formalism, where the symmetry properties of the system are incorporated by constructing a SO(4) generalization of the conventional fluctuation-exchange approximation (FLEX) coupled self-consistently to the dynamical ... More
A spin-orbital-intertwined nematic state in FeSeMar 14 2019Spin-orbit coupling (SOC) due to the relativistic motion of electrons is a fundamental interaction to intertwine spin and orbital degrees of freedom in solids. Recently, the fingerprint of SOC on the low-energy electronic structure has been observed in ... More
3D visualizations of nano-scale phase separation and ultrafast dynamic correlation between phases in (Na0.32K0.68)0.95Fe1.75Se2Mar 14 2019Phase separation of metallic and antiferromagnetic (AFM) insulating phases in alkaline iron selenides (AxFe2-ySe2) continues to attract intense interest because the relationship between two peculiar features probably is a key to clarifying the pairing ... More
Understanding Novel Superconductors with Ab Initio CalculationsMar 13 2019This chapter gives an overview of the progress in the field of computational superconductivity. Following the MgB2 discovery (2001), there has been an impressive acceleration in the development of methods based on Density Functional Theory to compute ... More
Coexistence of orbital and quantum critical magnetoresistance in FeSe$_{1-x}$S$_{x}$Mar 13 2019The recent discovery of a non-magnetic nematic quantum critical point (QCP) in the iron chalcogenide family FeSe$_{1-x}$S$_{x}$ has raised the prospect of investigating, in isolation, the role of nematicity on the electronic properties of correlated metals. ... More
Angular dependence of the upper critical field in the high-pressure $1T'$ phase of MoTe$_2$Mar 13 2019Superconductivity in the type-II Weyl semimetal candidate MoTe$_2$ has attracted much attention due to the possible realization of topological superconductivity. Under applied pressure, the superconducting transition temperature is significantly enhanced, ... More
Exactly Solvable Kondo Lattice Model in Anisotropic LimitMar 13 2019In this paper we introduce an exactly solvable Kondo lattice model without any fine-tuning local gauge symmetry. This model describes itinerant electrons interplaying with localized moment via only longitude Kondo exchange. Its solvability results from ... More
Unconventional Scaling of the Superfluid Density with the Critical Temperature in Transition Metal DichalcogenidesMar 13 2019Mar 18 2019We report on muon spin rotation experiments probing the temperature-dependent magnetic penetration depth in 2H-NbSe_2 under high-pressure (p_max = 2.1 GPa) and in 4H-NbSe_2 at ambient pressure. The current results for ambient pressure along with our earlier ... More
Unconventional Scaling of the Superfluid Density with the Critical Temperature in Transition Metal DichalcogenidesMar 13 2019We report on muon spin rotation experiments probing the temperature-dependent magnetic penetration depth in 2H-NbSe_2 under high-pressure (p_max = 2.1 GPa) and in 4H-NbSe_2 at ambient pressure. The current results for ambient pressure along with our earlier ... More
Uniaxial Strain Tuning of Superconductivity in 2$H$-NbSe$_{2}$Mar 12 2019We explore the effect of lattice anisotropy on the charge-ordered superconductor 2H-NbSe$_{2}$. Using a novel strain apparatus, we measure the superconducting transition temperature $T_{sc}$ as a function of uniaxial strain. It is found that $T_{sc}$ ... More
Tuning the electronic and magnetic properties of metal-doped phenanthrene by codoping methodMar 12 2019By first principles method, we have determined the geometric configuration of K/Ba-codoped phenanthrene based on the formation energy calculations, and systematically investigated its electronic and magnetic properties. There are two bands crossing Fermi ... More
A Renormalization-Group Study of Interacting Bose-Einstein condensates: Absence of the Bogoliubov Mode below Four ($T>0$) and Three ($T=0$) DimensionsMar 12 2019We derive exact renormalization-group equations for the $n$-point vertices ($n=0,1,2,\cdots$) of interacting single-component Bose-Einstein condensates based on the vertex expansion of the effective action. They have a notable feature of automatically ... More
Proximity effect and self-consistent field in a normal metal-superconductor structureMar 12 2019The concept of a self-consistent field in the theory of superconductivity based on the diagram method of the time-dependent perturbation theory is presented. It is shown that the well-known Bardeen-Cooper-Schrieffer equation for the order parameter of ... More
Detecting Dark Matter with Superconducting NanowiresMar 12 2019We propose the use of superconducting nanowires as both target and sensor for direct detection of sub-GeV dark matter. With excellent sensitivity to small energy deposits on electrons, and demonstrated low dark counts, such devices could be used to probe ... More
Charge and nematic orders in AFe$_2$As$_2$ (A= Rb,Cs) superconductorsMar 12 2019We discuss the results of $^{75}$As Nuclear Quadrupole Resonance (NQR) and muon spin relaxation measurements in AFe$_2$As$_2$ (A= Cs, Rb) iron-based superconductors. We demonstrate that the crossover detected in the nuclear spin-lattice relaxation rate ... More
Signature of a surface magnetic disorder in epitaxial TiN filmsMar 12 2019We analyze the evolution of the normal and superconducting electronic properties in epitaxial TiN films as a function of the film thickness with high Ioffe-Regel parameter values. As the film thickness decreases, we observe an increase of in the residual ... More
Engineering the Floquet spectrum of superconducting multiterminal quantum dotsMar 12 2019Here we present a theoretical investigation of the Floquet spectrum in multiterminal quantum dot Josephson junctions biased with commensurate voltages. We first draw an analogy between the electronic band theory and superconductivity which enlightens ... More
Time-reversal symmetry breaking superconductivity in hole-doped monolayer MoS$_{2}$Mar 12 2019We investigate the nature of the time-reversal breaking pairing state in the hole-doped monolayer MoS$_{2}$ on the basis of the realistic three-orbital attractive Hubbard-like model with the atomic spin-orbit coupling. Due to the multi-band features arising ... More
Single-crystal growth and extremely high H_c2 of 12442-type Fe-based superconductor KCa_2Fe_4As_4F_2Mar 12 2019Millimeter sized single crystals of KCa_2Fe_4As_4F_2 were grown using a self-flux method. The chemical compositions and crystal structure were characterized carefully. Superconductivity with the critical transition T_c = 33.5 K was confirmed by both the ... More
Entanglement in disordered superfluids: the impact of density, interaction and harmonic confinement on the Superconductor-Insulator transitionMar 12 2019We investigate the influence of density, interaction and harmonic confinement on the superfluid to insulator transition (SIT) in disordered fermionic superfluids described by the one-dimensional Hubbard model. We quantify the ground-state single-site ... More
Superfluid-Insulator Transition unambiguously detected by entanglement in one-dimensional disordered superfluidsMar 12 2019We use entanglement to track the superfluid-insulator transition (SIT) in disordered fermionic superfluids described by the one-dimensional Hubbard model. Entanglement is found to have remarkable signatures of the SIT driven by i) the disorder strength ... More
Novel dynamics and critical currents in fast superconducting vortices at high pulsed magnetic fieldsMar 11 2019Non-linear electrical transport studies at high-pulsed magnetic fields, above the range accessible by DC magnets, are of direct fundamental relevance to the physics of superconductors, domain-wall, charge-density waves, and topological semi-metal. All-superconducting ... More
The Nematic Energy Scale and the Missing Electron Pocket in FeSeMar 11 2019The multi-orbital nature of iron-based superconductors plays an important role in the fundamental physics of these materials. FeSe, while having the simplest structure among these materials, exhibits the effects of both nematicity and orbital-selective ... More
Enhanced, homogeneous type II superconductivity in Cu-intercalated PdTe$_2$Mar 11 2019Though the superconducting phase of the type-II Dirac semimetal PdTe$_2$ was shown to be conventional in nature, the phase continued to be interesting in terms of its magnetic properties. While certain experiments indicated an unexpected type-I superconducting ... More
A linear magnetic flux-to-voltage transfer function of differential DC SQUIDMar 11 2019A superconducting quantum interference device with differential output or "DSQUID" was proposed earlier for operation in the presence of large common-mode signals. The DSQUID is the differential connection of two identical SQUIDs. Here we show that besides ... More
Effects of the phase coherence on the local density of states in superconducting proximity structuresMar 11 2019We theoretically study the local density of states in superconducting proximity structure where two superconducting terminals are attached to a side surface of a normal-metal wire. Using the quasiclassical Green's function method, the energy spectrum ... More
Strong pinning in the hole-doped pnictide superconductor La$_{0.34}$Na$_{0.66}$Fe$_2$As$_2$Mar 10 2019We present magnetization studies as a function of time, temperature and magnetic field for $H$ $\parallel$ c-axis, in a hole-doped pnictide superconductor, La$_{0.34}$Na$_{0.66}$Fe$_2$As$_2$, with, $T_c$ $\approx$ 27 K. The obtained vortex phase-diagram ... More
Local Superconductivity in Vanadium Iron ArsenideMar 08 2019We investigate vanadium-doped iron arsenides, using novel crystals, to further fundamental understanding of quantum properties in unconventional superconductors. An (average) increase in c-lattice parameter of the BaFe2As2 lattice is observed with increasing ... More
Mesoscopic Al/Cu/Al Josephson field-effect transistorsMar 08 2019We demonstrate the first \textit{all-metallic} mesoscopic superconductor-normal metal-superconductor (SNS) field-effect controlled Josephson transistors (SNS-FETs) and show their full characterization from the critical temperature $T_c$ down to 50 mK ... More
Prediction of fundamental properties of Be-B-Ta based novel ternary compounds from first-principles calculationsMar 08 2019Be-B/B-Ta based compounds are very attractive to researchers because of their high density and ultra-hardness. But ternary Be-B-Ta compounds are neither synthesized nor predicted. In this paper, variable composition evolutionary crystal structure prediction ... More
Pressure-induced high temperature superconductivity in H3X (X=As, Se, Br, Sb, Te and I)Mar 08 2019The discovery of high critical temperature Tc superconductivity in highly compressed H3S has opened up the question of searching for strong electron-phonon coupling in the hydrides outside the transition metal series. In this work, we performed Linearized ... More
Spin stripe order in a square planar trilayer nickelateMar 08 2019Trilayer nickelates, which exhibit a high degree of orbital polarization combined with an electron count (d8.67) corresponding to overdoped cuprates, have been identified as a promising candidate platform for achieving high-Tc superconductivity. One such ... More
External field tunable superconducting transition temperature in Nb/Co/Py/Nb superconductor/exchange spring/superconductor filmsMar 07 2019Over the last decade it has been shown that magnetic non-collinearity at the superconductor-ferromagnet interface is a key ingredient for spin-singlet to spin-triplet pair conversion. This effect has been verified in several synthetic non-collinear magnetic ... More
$d_{x^2-y^2}$-wave density wave and $d_{x^2-y^2}$-wave superconducting gap on the extended Hubbard model on a square latticeMar 07 2019The extended Hubbard model with a nearest-neighbor Coulomb repulsion on the square lattice is studied to obtain insight into the phase diagram of cuprate high $T_c$ superconductors (HTS). To pursue the hidden-order scenario proposed in [S. Chakravarty ... More
Proximity effect in a ferromagnetic semiconductor with spin-orbit interactionsMar 07 2019We study theoretically the proximity effect in a ferromagnetic semiconductor with Rashba spin-orbit interaction. The exchange potential generates opposite-spin-triplet Cooper pairs which are transformed into equal-spin-triplet pairs by the spin-orbit ... More
Superconductivity in Bi3O2S2Cl with Bi-Cl Planar LayersMar 07 2019A quaternary compound Bi3O2S2Cl, which consists of novel [BiS2Cl]2-layers, is reported. It adopts a layered structure of the space group I4/mmm (No. 139) with lattice parameters: a = 3.927(1) {\AA}, c = 21.720(5) {\AA}. In this compound, bismuth and chlorine ... More
Control of superconducting pairing symmetries in monolayer black phosphorusMar 06 2019Motivated by recent experimental progress, we study the effect of mechanical deformations on the superconducting pairing symmetries in monolayer black phosphorus (MBP). Starting with phonon-mediated intervalley spin-singlet electron-electron pairing and ... More
Lattice Disorder Effect on Magnetic Ordering of Iron ArsenidesMar 06 2019This study demonstrates the tuning of Neel temperature via nano- and mesoscale structural features in an iron arsenide. Although magnetic ground states in quantum materials can be theoretically predicted from known crystal structures and chemical compositions, ... More
Rare earth Kitaev materialsMar 06 2019We continue the extension of the Kitaev physics and Kitaev interaction to the rare-earth magnets, and study the physical properties of the rare-earth based honeycomb lattice Kitaev materials. We are particularly interested in the experimental consequences ... More
Niobium diselenide superconducting photodetectorsMar 06 2019We report the photoresponse of niobium diselenide (NbSe$_2$), a transition metal dichalcogenide (TMD) which exhibits superconducting properties down to a single layer. Devices are built by using micro-mechanically cleaved 2 to 10 layers and tested under ... More
Unconventional Superconductivity in Heavy Fermion UTe2Mar 06 2019We grew single crystals of the recently discovered heavy fermion superconductor UTe2, and measured the resistivity, specific heat and magnetoresistance. Superconductivity (SC) was clearly detected at Tsc=1.65K as sharp drop of the resistivity in a high ... More
Type-I superconductivity in Al$_6$ReMar 06 2019While the pure elements tend to exhibit Type-I rather than Type-II superconductivity, nearly all compound superconductors are Type-II, with only a few known exceptions. We report single crystal growth and physical characterization of the rhenium aluminide ... More
Dynamic properties of asymmetric double Josephson junction stack with quasiparticle imbalanceMar 06 2019We study analytically and numerically the influence of the quasiparticle charge imbalance on the dynamics of the asymmetric Josephson stack formed by two inequivalent junctions: the fast capacitive junction $JJ_{1}$ and slow non-capacitive junction $JJ_{2}$. ... More
Superconductivity and Equation of State of Distorted fcc-Lanthanum above Megabar PressuresMar 06 2019Lanthanum (La) is the first member of the rare-earth series of elements that has recently raised considerable interest due to its unique superhydride LaH10 and its superconducting properties. Although several studies have found superconductivity and phase ... More
Observation of superconducting gap spectra of long-range proximity effect in Au/SrTiO$_3$/SrRuO$_3$/Sr$_2$RuO$_4$ tunnel junctionsMar 05 2019We observe an unconventional superconducting minigap induced into a ferromagnet SrRuO$_3$ from a spin-triplet superconductor Sr$_2$RuO$_4$ using a Au/SrTiO$_3$/SrRuO$_3$/Sr$_2$RuO$_4$ tunnel junction. Voltage bias differential conductance of the tunnel ... More
Field-induced transition to semion topological order from the square-lattice Néel stateMar 05 2019We study the quantum phase transition of a square-lattice antiferromagnet from a N\'eel state to a state with coexisting N\'eel and semion topological order. The transition is driven by an applied magnetic field and involves no change in the symmetry ... More
Field-induced transition to semion topological order from the square-lattice Néel stateMar 05 2019Mar 09 2019We study the quantum phase transition of a square-lattice antiferromagnet from a confining N\'eel state to a state with coexisting N\'eel and semion topological order. The transition is driven by an applied magnetic field and involves no change in the ... More
Spatial cross-correlations between local electron-electron interaction effects and local superconducting energy gap in moderately-disordered NbN ultrathin filmsMar 05 2019We have studied by scanning tunneling spectroscopy (STS) at very-low temperature the local electronic properties of a superconducting NbN disordered ultrathin film grown \emph{ex situ}. The NbN film has a $T_c = 3.8$~K about $0.25$ $T_{C-bulk}$. The STS ... More
Uniform hole doping in HgBa$_{2}$Ca$_{2}$Cu$_{3}$O$_{8+δ}$ studied by $^{63}$Cu NMRMar 04 2019We studied local magnetic properties of triple-CuO$_2$-layer superconductors HgBa$_2$Ca$_2$Cu$_3$O$_{8+\delta}$ with rich $^{63}$Cu isotope (underdoped $T_\mathrm{c}$ = 124 K and optimally doped $T_\mathrm{c}$ = 134 K) by $^{63}$Cu NMR spin-echo techniques. ... More
Reduced Density Matrix Functional Theory for SuperconductorsMar 04 2019We present an ab initio theory for superconductors, based on a unique mapping between the statistical density operator at equilibrium, on the one hand, and the corresponding one-body reduced density matrix $\gamma$ and the anomalous density $\chi$, on ... More
Superconductivity enhancement on a topological insulator surface by antiferromagnetic squeezed magnonsMar 04 2019We study magnon-mediated superconductivity in a heterostructure consisting of a topological insulator and an antiferromagnetic insulator on a bipartite lattice. Our main finding is that one may significantly enhance magnon-mediated superconductivity on ... More
Tuning topological orders by a conical magnetic field in the Kitaev modelMar 04 2019We show that a conical magnetic field ${\bf H}=(1,1,1)H$ can be used to tune the topological order and hence anyon excitations of the $\mathrm{Z_2}$ quantum spin liquid in the isotropic antiferromagnetic Kitaev model. A novel topological order, featured ... More
Superconducting size effect in thin films under electric field: mean-field self-consistent modelMar 04 2019We consider effects of an externally applied electrostatic field on superconductivity, self-consistently within a BCS mean field model, for a clean 3D metal thin film. The electrostatic change in superconducting condensation energy scales as $\mu^{-1}$ ... More
Sixfold enhancement of superconductivity in a tunable electronic nematic systemMar 03 2019The electronic nematic phase, wherein electronic degrees of freedom lower the crystal rotational symmetry, is a common motif across a number of high-temperature superconductors. However, understanding the role and influence of nematicity and nematic fluctuations ... More
Charge carrier dynamics of FeSe thin film investigated by terahertz magneto-optical spectroscopyMar 03 2019We performed terahertz magneto-optical spectroscopy of FeSe thin film to elucidate the charge carrier dynamics. The measured diagonal (longitudinal) and off-diagonal (Hall) conductivity spectra are well reproduced by two-carrier Drude model, from which ... More
Non-Kitaev spin liquids in Kitaev materialsMar 03 2019We point out that the Kitaev materials may not necessarily support Kitaev spin liquid. It is well-known that having a Kitaev term in the spin interaction is not the sufficient condition for the Kitaev spin liquid ground state. Many other spin liquids ... More
Large and significantly anisotropic critical current density induced by planar defects in CaKFe4As4 single crystalsMar 03 2019Three independent components of critical current density, one for the H//c axis and the other two for the H//ab plane, have been studied in CaKFe4As4 single crystals. When the magnetic field is applied along the c axis, we observed fish-tail-like peaks ... More
Large and significantly anisotropic critical current density induced by planar defects in CaKFe4As4 single crystalsMar 03 2019Mar 05 2019Three independent components of critical current density, one for the H//c axis and the other two for the H//ab plane, have been studied in CaKFe4As4 single crystals. When the magnetic field is applied along the c axis, we observed fish-tail-like peaks ... More
Full Proximity Treatment of Topological Superconductors in Josephson Junction ArchitecturesMar 03 2019Experiments on planar Josephson junction architectures have recently been shown to provide an alternative way of creating topological superconductors hosting accessible Majorana modes. These zero-energy modes can be found at the ends of a one-dimensional ... More
Evidence of energy-level quantization in YBa2Cu3O7-x phase-slip nanowiresMar 03 2019Superconducting nanowires are considered to be promising for the development of novel devices operating on quantum principles. We fabricated ultra-thin YBa2Cu3O7-x nanowires with phase-slip dynamics and studied the switching-current statistics at temperatures ... More
Doping and momentum dependence of coupling strength in cuprate superconductorsMar 03 2019Superconductivity is caused by the interaction between electrons by the exchange of collective bosonic excitations, however, this bosonic glue forming electron pairs is manifested itself by the coupling strength of the electrons to collective bosonic ... More
Photoinduced ultrafast dynamics of local nematicity and lattice distortions in FeSe crystalsMar 03 2019Formation of electronic nematicity is a common thread of unconventional superconductors. In iron-based materials, the long-range nematic order is revealed by the orthorhombic lattice distortion, which importance is a highly controversial topic due the ... More
Fluxon interaction with the finite-size dipole impurityMar 02 2019Interaction of the fluxon with the finite size dipole impurity in the long Josephson junction is investigated. The impurity has polarity and will be referred to as a {\it dipole} impurity because it also has a direction and, consequently, changes its ... More
Superconductivity in Potassium-intercalated Td-WTe2Mar 02 2019To realize topological superconductor is one of the most attracting topics because of its great potential in quantum computation. In this study, we successfully intercalate potassium (K) into the van der Waals gap of type II Weyl semimetal WTe2, and discover ... More
Quantitative Comparison between Electronic Raman Scattering and Angle-Resolved Photoemission Spectra in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ Superconductors: Doping Dependence of Nodal and Antinodal Superconducting GapsMar 02 2019Both electronic Raman scattering (ERS) and angle-resolved photoemission spectra (ARPES) revealed two energy scales for the gap in different momentum spaces in the cuprates. However, the interpretations were different, and the gap values were also different ... More
Anomalous Knight shift and low-energy spin dynamics in the nematic state of FeSe$_{\rm 1-x}$S$_{\rm x}$Mar 01 2019The interplay between the nematic order and magnetism in FeSe is not yet well understood. There is a controversy concerning the relationship between orbital and spin degrees of freedom in FeSe and their relevance for superconductivity. Here we investigate ... More
Signature of Dispersing 1D Majorana Channels in an Iron-based SuperconductorMar 01 2019The possible realization of Majorana fermions as quasiparticle excitations in condensed matter physics has created much excitement. Most recent studies have focused on Majorana bound states which can serve as topological qubits. More generally, akin to ... More
Ultranodal pair states in iron-based superconductorsMar 01 2019We show that multiband superconductors with dominant spin singlet, intraband pairing of spin-1/2 electrons can undergo a transition to a state with Bogolibuov Fermi surfaces -- surfaces of zero energy excitations that are topologically protected in the ... More
Dynamical Josephson Effects in Atomically-Thin NbSe$_2$Mar 01 2019Mar 06 2019The advent of atomically-thin materials has ushered new platforms for studying condensed-matter physics in two-dimensions. Recently, there has been a strong thrust towards isolating graphene-like material with interactions between the carriers making ... More
Dynamical Josephson Effects in Atomically-Thin NbSe$_2$Mar 01 2019The advent of atomically-thin materials has ushered new platforms for studying condensed-matter physics in two-dimensions. Recently, there has been a strong thrust towards isolating graphene-like material with interactions between the carriers making ... More
Broken mirror symmetry, incommensurate spin correlations, and $B_{2g}$ nematic order in iron pnictidesMar 01 2019Motivated by growing indications for a distinct form of nematic correlations in the extremely hole doped iron pnictide compounds $A$Fe$_2$As$_2$ ($A$=K,Rb,Cs), we consider spin-driven nematic order in the general case of incommensurate magnetic fluctuations. ... More
Band Structure of Overdoped Cuprate Superconductors: Density Functional Theory Matching ExperimentsMar 01 2019A comprehensive angle resolved photoemission spectroscopy study of the band structure in single layer cuprates is presented with the aim of uncovering universal trends across different materials. Five different hole- and electron-doped cuprate superconductors ... More
Direct Dispersive Monitoring of Charge Parity in Offset-Charge-Sensitive TransmonsMar 01 2019A striking characteristic of superconducting circuits is that their eigenspectra and intermode coupling strengths are well predicted by simple Hamiltonians representing combinations of quantum circuit elements. Of particular interest is the Cooper-pair-box ... More
Doping-type-dependent pairing symmetry in predicted Ni-based high-$T_c$ superconductor La$_2$Ni$_2$Se$_2$O$_3$Feb 28 2019We study the electronic instabilities of newly predicted Ni-based high-$T_c$ superconducting material La$_2$Ni$_2$Se$_2$O$_3$ based on the random phase approximation. Our calculations on the susceptibility indicate that the collinear antiferromagnetic ... More
Local structure and Fe-vacancy disorder to order crossover in K$_x$Fe$_{2-y}$Se$_{2-z}$S$_z$Feb 28 2019The detailed account of the local atomic structure and structural disorder at 5~K across the phase diagram of K$_x$Fe$_{2-y}$Se$_{2-z}$S$_z$ $(0 \leq z \leq 2)$ high temperature superconductor is obtained from neutron total scattering and associated atomic ... More
Quantum phase transition inside the superconducting dome of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ probed by optical magneto-sensing using NV-centers in diamondFeb 28 2019While unusual normal state properties, such as non-Fermi liquid behavior of the resistivity, are commonly associated with strong quantum fluctuations, evidence for its presence inside the superconducting dome are much scarcer. In this paper, we use sensitive ... More
Topological $d$-wave Superconductivity and Nodal Line-Arc Intersections in Weyl SemimetalsFeb 28 2019Superconducting Weyl semimetals present a novel and promising system to harbor new forms of unconventional topological superconductivity. Within the context of time-reversal symmetric Weyl semimetals with $d$-wave superconductivity, we demonstrate that ... More
Topological superconductivity in planar Josephson junctions -- narrowing down to the nanowire limitFeb 28 2019We theoretically study topological planar Josephson junctions (JJs) formed from spin-orbit-coupled two-dimensional electron gases (2DEGs) proximitized by two superconductors and subjected to an in-plane magnetic field $B_\parallel$. Compared to previous ... More
Quenched nematic criticality separating two superconducting domes in an iron-based superconductor under pressureFeb 28 2019The nematic electronic state and its associated nematic critical fluctuations have emerged as potential candidates for superconducting pairing in various unconventional superconductors. However, in most materials their coexistence with other magnetically-ordered ... More
Ferromagnetic order in a cuprate superconductorFeb 28 2019The unexplained normal state and superconducting (SC) properties of the cuprates are believed to arise from doping an antiferromagnetic (AFM) Mott insulator. The competition between the AFM and SC can explain the increase in the SC transition temperature ... More
Mottness induced phase decoherence suggests Bose-Einstein condensation in overdoped cuprate high-temperature superconductorsFeb 28 2019Recent observations of diminishing superfluid phase stiffness in overdoped cuprate high-temperature superconductors challenges the conventional picture of superconductivity. Here, through analytic estimation and verified via variational Monte Carlo calculation ... More
3D quench modeling based on T-A formulation for high temperature superconductor CORC cablesFeb 28 2019High temperature superconductor (HTS) (RE)Ba2Cu3Ox (REBCO) conductor on round core cable (CORC) has high current carrying capacity for high field magnet and power applications. In REBCO CORC cables, current redistribution occurs among tapes through terminal ... More
The direction of the $d$-vector in a nematic triplet superconductorFeb 28 2019We investigate the states of triplet pairing in a candidate nematic superconductor versus typical material parameters, using the mean field theory for two- and three-dimensional tight-binding models with local triplet pairing in the $E_u$ representation. ... More
Origin of flat-band superfluidity on the Mielke checkerboard latticeFeb 28 2019The Mielke checkerboard is known to be one of the simplest two-band lattice models exhibiting an energetically flat band that is in touch with a quadratically dispersive band in the reciprocal space, i.e., its flat band is not isolated. Motivated by the ... More
Intertwined spin-orbital coupled orders in the iron-based superconductorsFeb 27 2019The underdoped phase diagram of the iron-based superconductors exemplifies the complexity common to many correlated materials. Indeed, multiple ordered states that break different symmetries but display comparable transition temperatures are present. ... More