Superconductivity
The search for conventional superconductors with high transition temperatures ($T_c$) has largely focused on intrinsically metallic compounds. In this work, we explore the potential of intrinsically non-metallic compounds to exhibit…
We formulate a duality transformation for a bilayer XY model where the layers are coupled by second order Josephson effect, which favors inter-layer phase difference of either $0$ or $\pi$. The model may represent a bilayer superconductor…
The transition metal dichalcogenide 4H$_{b}$-TaS$_{2}$ exhibits characteristics of topological edge modes and two-component superconductivity with time-reversal symmetry breaking (TRSB). The nature of the superconducting order parameter is…
Complex phase diagrams are generic feature of quantum materials that display high temperature superconductivity. In addition to d-wave superconductivity (or other unconventional states), these phase diagrams typically include various forms…
This work proposes a higher-order iterative framework for solving matrix equations, inspired by the structure and functionality of neural networks. A modification of the classical Jacobi iterative method is introduced to compute…
La$_2$NiO$_4$ is an antiferromagnetic insulator with a structural resemblance to its cuprate counterpart, La$_2$CuO$_4$. However, La$_2$CuO$_4$ has a Cu$^{2+}$ or 3$d^9$ electronic configuration that needs to be hole or electron doped for…
We study a multi-terminal Josephson junction consisting of a central spin-orbit-coupled (SOC) region with an in-plane Zeeman field connected to four superconducting terminals. This setup allows for the simultaneous measurement of both…
A highly effective method of the device linearity calculation on the stage of the device development is worked out and reported. The method allows expressing the linearity in terms of the achievable spurious-free dynamic range (SFDR) of the…
The ultimate spatial limit to establish a Josephson coupling between two superconducting electrodes is an atomic-scale junction. The Josephson effect in such ultrasmall junctions has been used to unveil new switching dynamics, study…
Recent experiments on bulk and thin film bilayer nickelate high-$T_c$ superconductors urge for clarification of their pairing mechanism. Debates exist on whether the hybridization or the Hund's coupling between the nickel $d_{x^2-y^2}$ and…
Chiral superconductors have long been theorized to break time-reversal symmetry and support exotic topological features such as Majorana modes and spontaneous edge currents, promising ingredients for quantum technologies. Although several…
The vibrational modes in Sr$_2$RuO$_4$ easily induce octahedral rotations without tilting. Being on the verge of a magnetic instability, such propensity of octahedral rotation may also produce magnetic fluctuations. In this work, we analyze…
Research on nickel-based superconductors has progressed from infinite-layer LaNiO$_2$ to finite-layer La$_{6}$Ni$_{5}$O$_{12}$, and most recently to the Ruddlesden-Popper phase La$_3$Ni$_2$O$_7$, which was found to exhibits onset of…
The recent discovery of high-temperature superconductivity in hole-doped SmNiO$_2$, exhibiting the record-high transition temperature $T_c$ among infinite-layer (IL) nickelates, has opened a new avenue for exploring design principles of…
We investigate superconductivity in a two-dimensional material described by a two-band heavy-fermion model, where hybridization between a dispersive band and a flat band introduces a quasi-flat dispersion to the otherwise localized…
We consider Josephson junctions formed by coupling two conventional superconductors via an unconventional magnet and investigate the formation of Andreev bound states, their impact on the Josephson effect, and the emergent superconducting…
Hole-doping of covalent materials has long served as a blueprint for designing conventional high-$T_{\rm c}$ superconductors, but thermodynamic constraints severely limit the space of realizable compounds. Our ab initio results indicate…
The underdoped cuprate superconductors are characterized by the opening of the pseudogap, while such an aspect of the pseudogap effect should be reflected in the low-energy electronic structure (LEES). Here the effect of the pseudogap on…
Kagome metals $A$V$_3$Sb$_5$ ($A=$ K, Rb, Cs) provide a compelling platform to explore the interplay between superconductivity (SC) and charge-density-wave (CDW) orders. While distinct CDW orders have been identified in K/RbV$_3$Sb$_5$…
We report the first observation of a momentum-resolved superconducting gap in the Hg-based trilayer cuprate, which holds the highest record of superconducting transition temperature ($T_\mathrm{c}$) at ambient pressure. By angle-resolved…