In 2012, we discovered new layered superconductors whose superconducting states emerge in the BiS2 layers. Since their crystal structure, composed of alternate stacks of BiS2 conduction layers and electrically insulating (blocking) layers, is similar...
Increasing and improving the critical transition temperature (TC), current density (JC) and the Meissner effect (HC) of conventional superconductors are the most important problems in superconductivity research, but progress has been slow for many ye...
In the stoichiometric iron-based superconductor EuRbFe4As4, superconductivity coexists with a long-range magnetic ordering in Eu layers. Using high-resolution transmission electron microscopy (HRTEM), we observed an atomic structure of as-grown EuRbF...
High-temperature superconductors (HTS) are being increasingly used for magnet applications. One of the known challenges of practical conductors made with high-temperature superconductor materials is a slow normal zone propagation velocity resulting f...
We study the Josephson current (supercurrent) in a system consisting of two superconductors connected to a single-level quantum dot (QD), which is also side-coupled to a nanowire hosting Majorana bound states (MBSs). Our results show that the MBSs ch...
We study the transport and the superconducting dynamics in a layer of type II superconductor (SC) with a normal top layer that hosts a helical magnetic ordering that gives rise to spin-current-driven ferroelectric polarization. Proximity effects akin...
A self-consistent two-gap γ -model is used to quantitatively describe several thermodynamic properties of MgB 2 superconductor. The superconducting coupling matrix, ν i j , was obtained from the fitting of the superflui...
We report a systematic study on the thickness-dependent superconductivity and transport properties in exfoliated layered topological superconductor β-PdBi2. The superconducting transition temperature Tc is found to decrease with the decreasing thickn...
We investigate the gap symmetry of the topological superconductor candidate HfRuP, which crystallizes in a noncentrosymmetric hexagonal crystal structure, using muon spin rotation/relaxation (μSR) measurements in transverse-field (TF) geometry. Th...
The crystal growth of high-temperature oxide superconductors has been hampered by the complexities of these materials and the lack of knowledge of corresponding phase diagrams. The most common crystal growth technique adopted for these materials is t...
We investigate single-particle excitation properties in the normal state of a two-band superconductor or superfluid throughout the Bardeen–Cooper–Schrieffer (BCS) to Bose–Einstein-condensation (BEC) crossover, within the many-body T-matrix approximat...
Superconducting wires are widely used for fabricating magnetic coils in fusion reactors. Superconducting magnet system represents a key determinant of the thermal efficiency and the construction/operating costs of such a reactor. In consideration of...
Ca1−xLaxFeAs2 (CLFA112) belongs to a new family of Fe-based superconductors (FeSCs) and has a unique crystal structure featuring an arsenic zigzag chain layer, which has been proposed to be a possible two-dimensional topological insulator. This...
A method is proposed to extend the zero-temperature Hall-Klemm microscopic theory of the Knight shift K in an anisotropic and correlated, multi-band metal to calculate K ( T ) at finite temperatures T both above and into its superconducting s...
As known, the realistic, exponential, fall-off of the rate of production of light mesons in the chromo-electric field of a quark–antiquark string, as a function of the meson mass, can be obtained from the Schwinger-formula Gaussian fall-off wit...
A large drilled single domain SmBa2Cu3O7−δ (SmBCO) bulk superconductor with a diameter of 32 mm and different hole sizes was successfully fabricated using the modified top-seeded infiltration and growth (TSIG) process. The morphology, superconducting...
We theoretically investigate the optical bistability in superconductor–semiconductor photonic crystals composed of graphene. The photonic crystals are symmetric to the center and arranged alternately by the superconductor (HgBa2Ca2Cu3O8+δ...
The onset of superconductivity at the transition temperature is marked by the onset of order, which is characterized by an energy gap. Most models of the iron-based superconductors find a sign-changing (s±) order parameter [1–6], with the physical im...
I solved the Eliashberg equations for a multiband non-phononic s± wave spin-glass superconductor, calculating the temperature dependence of the gaps and of superfluid density. Their behaviors were revealed to be unusual: showing non-monotonic...
Magnesium diboride (MgB2) superconductor combines many unique features such as transparency of its grain boundaries to super-current flow, large coherence length, absence of weak links and small anisotropy. Doping is one of the mechanisms for enhanci...
We investigated the effect of 0.6 MeV proton irradiation on the superconducting and normal-state properties of thin-film YBa2Cu3O7−δ superconductors. A thin-film YBCO superconductor (≈567 nm thick) was subject to a series of proton...
The role of a layered structure in superconducting pinning properties is still at a debate. The effects of the vortex shape, which can assume for example a staircase form, could influence the interplay with extrinsic pinning coming from the specific...
We construct a holographic p-wave superconductor with excited states in the 4D Einstein–Gauss–Bonnet gravity using the Maxwell complex vector field model. In the probe limit, we observe that, the higher curvature correction or the higher...
Energy dissipation from vortex motion, which appears as a resistivity of the mixed-state superconductor, limits the range of type II superconductors in low- and high-power electronics and optoelectronics. The level of dissipation increases with the d...
The important factors in obtaining a high-quality superconducting joint were investigated for the superconducting joint of a GdBa2Cu3Ox (GdBCO) bulk superconductor with sintered ErBa2Cu3Ox (ErBCO) using the local melt-growth method. REBCO (RE: rare e...
The band structure and the Fermi surface of the recently discovered superconductor (EMIM)xFeSe are studied within the density functional theory in the generalized gradient approximation. We show that the bands near the Fermi level are formed primaril...
The smart meta-superconductor MgB2 and Bi(Pb)SrCaCuO increase the superconducting transition temperature (TC), but the changes in the transport critical current density (JC) and Meissner effect are still unknown. Here, we investigated the JC and Meis...
The development of solids with the requested chemical and physical properties requires a thorough understanding of their electronic structures, as proper knowledge of the electronic structure of a given solid provides invaluable information regarding...
The multiseeding technique is a method to grow large-sized REBa2Cu3O7−δ (REBCO, where RE is a rare earth element) high temperature superconducting bulks. However, due to the existence of grain boundaries between seed crystals, the superco...
Majorana bound states in topological superconductors have attracted intense research activity in view of applications in topological quantum computation. However, they are not the only example of topological bound states that can occur in such system...
The low-temperature scanning tunneling microscope and spectroscopy (STM/STS) are used to visualize superconducting states in the cleaved single crystal of 9% praseodymium-doped CaFe2As2 (Pr-Ca122) with Tc ≈ 30 K. The spectroscopy shows strong spatial...
The noncentrosymmetric NbReSi superconductor with Tc≃6.5 K is characterized by the relatively large upper critical magnetic field. Its multigap features were observed experimentally. Recent studies suggested the realization of P6¯2m or Ima...
Bulk high-temperature superconductors (HTSs) such as REBa2Cu3O7−x (REBCO, RE = Y, Gd) are commonly used in rotationally symmetric superconducting magnetic bearings. However, such bulks have several disadvantages such as brittleness, limited ava...
Low-temperature variable-energy electron irradiation was used to induce non-magnetic disorder in a single crystal of a hole-doped iron-based superconductor, Ba1−xKxFe2As2, x = 0.80. To avoid systematic errors, the beam energy was adjusted non-c...
Since the discovery of cuprates (Cu-oxide superconductors) in 1986 [1–4], layered superconductors have attracted much attention, due to the emergence of high-transition-temperature (high-Tc) and unconventional superconductivity.
The classical Bardeen–Cooper–Schrieffer and Eliashberg theories of the electron–phonon-mediated superconductivity are based on the Migdal theorem, which is an assumption that the energy of charge carriers, kBTF, significantly exceed...
The experimental discovery that compressed sulfur hydride exhibits superconducting transition temperature of Tc=203 K by Drozdov et al. (Nature 2015, 525, 73–76) sparked studies of compressed hydrides. This discovery was not a straigh...
First-principles calculations for underdoped La2−xSrxCuO4 (LSCO) have revealed a Fermi surface consisting of spin-triplet (KS) particles at the antinodal Fermi-pockets and spin-singlet (SS) particles at the nodal Fermi-arcs in the presence of A...
A smart meta-superconductor Bi(Pb)SrCaCuO (B(P)SCCO) may increase the critical transition temperature (TC) of B(P)SCCO by electroluminescence (EL) energy injection of inhomogeneous phases. However, the increase amplitude ΔTC (ΔTC=TC−TC,pure) of TC is...
Evidence of inhomogeneous superconductivity, in this case superconductivity with a spatially modulated superconducting order parameter, has now been found in many materials and by many measurement methods. Although the evidence is strong, it is circu...
Based on the transfer-matrix method, we theoretically explore the transmission and reflection properties of light waves in a one-dimensional defective photonic crystal composed of superconductor (HgBa2Ca2Cu3O8+δ) and semiconductor (GaAs) layers...
We design and evaluate the performance of a one-dimensional photonic crystal (PhC) optical filter that comprises the integration of alternating layers of a barium titanate ferroelectric (BaTiO3) and an yttrium oxide dielectric (Y2O3), with a critical...
We theoretically investigate the defect mode transmittance of light waves in superconductor–semiconductor photonic crystals and its pressure-sensing dependence. The photonic crystal is composed of alternating superconducting and semiconducting...
This study investigates the gap-to-Tc ratio (R) of yttrium hydride superconductors within the weak coupling limit. We derived an analytical formula for the gap-to-Tc ratio. The ratio of the gap-to-Tc is dependent on the pressure applied to each super...
Coupling superconducting (SC) contacts to light-emitting layers can lead to remarkable effects, as seen in inorganic quantum-well LEDs with superconducting contacts, where an enhancement in radiative recombination was observed. Additional dramatic ef...
Layered superconductors are attractive because some of them show high critical temperatures. While their crystal structures are similar, these compounds are composed of many elements. Compounds with many elements tend to be incongruent melting compou...
Structural transformation and magnetic ordering interplays for emergence as well as suppression of superconductivity in 122-iron-based superconducting materials. Electron and hole doping play a vital role in structural transition and magnetism suppre...
Thin superconducting films have been a significant part of superconductivity research for more than six decades. They have had a significant impact on the existing consensus on the microscopic and macroscopic nature of the superconducting state. Thin...
Inverse least squares numerical optimization, 3D/4D interior optimization, and 3D/4D graphical optimization software and algorithm programming have been presented in a series of previous articles on the applications of the BCS theory of superconducti...
The nano-size effects of high-Tc cuprate superconductor La2−xSrxCuO4 with x = 0.20 are investigated using X-ray diffractometry, Transmission electron microscopy, and muon-spin relaxation (μSR). It is investigated whether an increase in the b...
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