Superconductivity
Like electrons, Cooper pairs can carry a monopole charge if the pairing electrons come from two or more Fermi surfaces with different Chern numbers. In such an instance, a superconductor is necessarily nodal due to an inherent topological…
Formation of vortices is a typical phenomenon of type-II superconductors under magnetic fields (H). In contrast, type-I superconductors do not host vortices because of their Meissner state. As rare cases, vortices have been observed in…
Two-dimensional (2D) intrinsic superconductors with nontrivial topological band and vertical ferroelectricity exhibit fascinating characteristics to achieving electrostatic control of quantum phases. While, only a few such 2D materials have…
Two-dimensional semiconductor-superconductor heterostructures form the foundation of numerous nanoscale physical systems. However, measuring the properties of such heterostructures, and characterizing the semiconductor in-situ is…
A key challenge in materials discovery is to find high-temperature superconductors. Hydrogen and hydride materials have long been considered promising materials displaying conventional phonon-mediated superconductivity. However, the high…
The combination of a superconductor with a magnetically inhomogeneous material has been established as an efficient mechanism for the generation of long-ranged spin-polarized (spin-triplet) Cooper pairs. Evidence for this mechanism,…
Logic circuits consist of devices that can be controlled between two distinct states. The recent demonstration that a superconducting current flowing in a constriction can be controlled via a gate voltage ($V_G$) - can lead to…
Josephson diodes are superconducting elements that show an asymmetry in the critical current depending on the direction of the current. Here, we theoretically explore how an alternating current bias can tune the response of such a diode. We…
Motivated by the recent observation of superconductivity with $T_c \sim 80$ K in pressurized La3Ni2O7 [Nature 621, 493 (2023)], we explore the structural and electronic properties in A3Ni2O7 bilayer nickelates (A=La-Lu, Y, Sc) as a function…
A material called LK-99, a modified-lead apatite crystal structure with the composition Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O ($0.9<x<1.1$) has been reported to be an above-room-temperature superconductor at ambient pressure. It is hard to expect…
We report on magnetron deposition of thin superconducting rhenium films on sapphire substrates. During the deposition, substrates were held at ambient temperature. Critical temperature of the films is Tc~3.6 K. Films have polycrystalline…
Recent Josephson tunneling experiments on twisted flakes of high-$T_c$ cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ revealed a non-reciprocal behavior of the critical interlayer Josephson current - i.e., a Josephson diode effect.…
Based on a time-dependent Ginzburg-Landau system of equations and finite element modeling, we present novel results related with the physics of phase-slippage in superconducting wires surrounded by a non-superconductive environment. These…
High-entropy alloy (HEA) superconductors have attracted significant attention due to their exceptional low-temperature mechanical and superconducting properties. We report the synthesis and thorough characterization of an equiatomic HEA…
We consider the vestigial phase with broken time-reversal symmetry above the superconducting transition temperature of a two-component superconductor in two spatial dimensions. We show that, in contrast to 3D, a vestigial phase is in…
Superconducting transition, defined as vanishing of the resistivity, under a magnetic field in a clean bulk type II superconductor with weak sample disorder is believed to be a reflection of freezing of the vortex liquid to a kind of vortex…
We present nuclear magnetic resonance data in BaFe$_2$As$_2$ in the presence of pulsed strain fields that are interleaved in time with the radiofrequency excitation pulses. In this approach, the precessing nuclear magnetization acquires a…
We present nuclear magnetic (NMR) and qudrupole (NQR) resonance and magnetization data in the normal state of the topological crystalline superconductor LaNiGa$_2$. We find no evidence of magnetic fluctuations or enhanced paramagnetism.…
In underdoped cuprate high $T_{\mathrm{c}}$ superconductors, various local orders and symmetry breaking states, in addition to superconductivity, reside in the CuO$_2$ planes. The confinement of the CuO$_2$ planes can therefore play a…
We investigate the effects of a Laguerre-Gaussian (LG) beam on the superconducting state. We show that the vortex angular momentum of a LG beam affects the superconducting state and induces currents. The induction of the current by light is…