Superconductivity
We solve the two-electron problem on a square lattice with $d$-wave altermagnetism, considering both on-site and nearest-neighbor attractive interactions. The altermagnetic spin-splitting in the single-particle dispersion naturally gives…
Quasi-one-dimensional RbMn$_{6}$Bi$_{5}$, the first pressure-induced ternary Mn-based superconductor, exhibits a phase diagram analogous to those of cuprate and iron-based superconductors, with superconductivity neighboring…
A strong correlation between zero-temperature superfluid density ($\rho_{s0}$) and transition temperature ($T_c$) is considered as a hallmark of unconventional superconductivity. However, their relationship has yet to be unveiled in…
We investigate spin-valley instabilities and their connection to the reentrant superconducting states recently observed in the twisted bilayer dichalcogenide WSe$_2$ at a $5^o$ twist angle. Starting from an effective three-orbital faithful…
We investigate how strongly broken spatial symmetries affect the Kohn--Luttinger (KL) mechanism, in which superconductivity emerges purely from repulsive interactions. While the original KL argument assumes continuous rotational symmetry,…
Characterizing magnetic fluctuations is one of the keys to understanding the origin of superconductivity in the spin-triplet superconductor UTe$_2$ which exhibits two superconducting (SC) phases (SC1 and SC2) under pressure: SC1 where a…
Many years of intense research on cuprate superconductors have led to several discoveries, such as the pseudogap and charge density waves (CDW), yet a complete theory is still lacking. By analyzing some experiments and performing…
The binary metal borides provide a promising platform for searching unique materials with superconductivity and super-hardness under high pressure, owing to the distinctive bonding characters of boron. In this work, combined the…
We present a new probe for the first-order transition for layered vortex matter: A second step in the screening of an ac field that is independent of the frequency and amplitude of the excitation. This second step is observed in the…
Controlling nonequilibrium dynamics in quantum materials requires ultrafast probes with spectral selectivity. We report femtosecond reflectivity measurements on the cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ using…
We report on results of simulations and experiments of vortex states in superconducting micro-wires with periodic rectangular pinhole structures. The simulations have been performed by means of numerically solving the time-dependent…
Rare-earth superhydrides have attracted considerable attention because of their high critical superconducting temperature under extreme pressures. They are known to have localized valence electrons, implying strong electronic correlations.…
We show that vortices with circulating current, related with odd-frequency triplet pairing, appear in Josephson junctions where the barrier is a weak ferromagnet with strong spin-orbit coupling. By symmetry analysis we show that there is an…
In 1965 Kohn and Luttinger proposed a genuine electronic mechanism for superconductivity. Despite the bare electrostatic interaction between two electrons being repulsive, in a metal electron-hole fluctuations can give rise to Friedel…
The recent discovery of superconductivity in pressurized Ruddlesden-Popper (RP) nickelates has provided new perspectives on the mechanism of high-temperature superconductivity. Up to now, most experiments concentrated on the…
We report pressure-induced superconductivity in the spinel CuIr$_{2}$S$_{4}$ with a transition temperature ($T_{\text{c}}$) reaching \textbf{18.2 K}, establishing a new record for this class of materials and surpassing the decades-old limit…
We report on two mechanisms of angularly selective enhanced screening in the solid vortex phase of extremely layered superconductors with tilted columnar defects (CDs). We study Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ samples with different…
In the Meissner phase of a superconductor, an external constant magnetic field is shielded by circulating persistent zero-resistance supercurrents that are formed by Cooper pairs. However, a thermodynamic change of state within this phase,…
In this work, we demonstrate that the intrinsic timescale of a Josephson junction can be controlled through dynamical vacuum selection. By applying a Kapitza-like high-frequency drive to the system, the effective Josephson potential is…
Using constrained-path quantum Monte Carlo, we map the ground-state phase diagram versus the nearest-neighbor (NN) attraction $V$ and spin-dependent hopping anisotropy $\alpha$ for the two-dimensional attractive $t$--$U$--$V$ Hubbard model…