Superconductivity
Isotope effect with a large coefficient $\alpha=-\partial \ln T_c/\partial \ln M$ is usually taken as an evidence of phonon mediated superconductors in the Bardeen-Cooper-Schrieffer (BCS) theory. However, in cuprates which are now widely…
The bound states around a vortex in anisotropic superconductors is a longstanding yet important issue. In this work, we develop a variational theory on the basis of the Andreev approximation to obtain the energy levels and wave functions of…
Proximity effect at superconductor/antiferromagnet (S/AF) interfaces, which manifests itself as generation of Neel-type triplet correlations, leads to sensitivity of the superconducting critical temperature to the mutual orientation of the…
A theory of strong coupling superconductivity in uranium compounds has been developed, based on electron-electron interaction through magnetic fluctuations described by frequency-dependent magnetic susceptibility. The magnetic field…
The superconducting state with the usual 2e-flux quantization formed from a normal state with 3Q charge density or loop-current order is a linear combination of 3 different paired states with an overall gauge invariant phase and two…
Realizing topological superconductivity by integrating high-transition-temperature ($T_C$) superconductors with topological insulators can open new paths for quantum computing applications. Here, we report a new approach for increasing the…
In this work we study the role of the heat diffusion equation in simulating the resistive state of superconducting films. By analyzing the current-voltage and current-resistance characteristic curves for temperatures close to $T_c$ and…
To clarify the nature of high-temperature superconductivity in the bilayer nickelate La$_3$Ni$_2$O$_7$ under pressure, we investigate, using the density-matrix renormalization group method, the pair correlations in the two-orbital $t$-$J$…
In Josephson diodes the asymmetry between positive and negative current branch of the current-phase relation leads to a polarity-dependent critical current and Josephson inductance. The supercurrent nonreciprocity can be described as a…
Inspired by the first boron-carbon (B-C) clathrate SrB$_3$C$_3$ and the ternary borohydride KB$_2$H$_8$ [Miao et al., Phys. Rev. B 104 L100504 (2021)], we have performed first-principles density functional theory calculations of the…
Ordinary superconductors are widely assumed insensitive to small concentrations of random nonmagnetic impurities, whereas strong disorder suppresses superconductivity, ultimately leading to a superconductor-insulator transition. In between…
We propose a superconducting diode device comprising a central superconducting film flanked by two wires carrying an applied DC bias, suitably chosen so as to generate different asymmetric field profiles. Through numerical simulations of…
At interfaces connecting two superconductors (SCs) separated by a metallic layer, an electric current is induced when there is a disparity in the phases of the two superconductors. We elucidate this phenomenon based on the weights of the…
Recently, the two-site Kitaev model hosting Majorana edge states was experimentally realized based on double quantum dots. In this context, we construct two-band effective models describing Majorana edge states of a finite-length Kitaev…
Nickelate superconductors are outstanding materials with intriguing analogies with the cuprates. These analogies suggest that their superconducting mechanism may be unconventional, although this fundamental question is currently under…
We study the interplay of vortices and disorder in a two-dimensional disordered superconductor at zero temperature described by the Bogoliubov-de Gennes (BdG) self-consistent formalism for lattices of sizes up to $100\times100$ where the…
Topological materials are renowned for their ability to harbor states localized at their peripheries, such as surfaces, edges, and corners. Accompanying these states, fractional charges appear on peripheral unit cells. Recently,…
Two-dimensional materials are of interest for their exotic properties, for example, superconductivity, and highly tunability. Focusing on phonon-mediating superconductivity, one would propose to promote critical temperature by substituting…
Metallic transition metal dichalcogenides (TMDs), consisting of H-NbSe$_2$, H-NbS$_2$, H-TaSe$_2$ and H-TaS$_2$, remain superconducting down to a thickness of a single layer. In these materials, thickness affects a variety of properties,…
Motivated by recent advancements highlighting Ta as a promising material in low-loss superconducting circuits and showing long coherence times in superconducting qubits, we have explored the effect of cryogenic temperatures on the growth of…