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arXiv · 2512.01266

Topological superconductivity and superconducting diode effect mediated via unconventional magnet and Ising spin-orbit coupling

Amartya Pal·Debashish Mondal·Tanay Nag·Arijit Saha
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Abstract

We propose a theoretical framework in which a one-dimensional (1D) tight-binding model incorporating unconventional magnetic order together with Rashba and Ising spin-orbit couplings are considered to realize two key phenomena in condensed matter systems: topological superconductivity and the superconducting diode effect (SDE). We first elucidate the underlying band topology of the normal-state Hamiltonian and subsequently introduce an on-site attractive Hubbard interaction. Performing a a self-consistent mean-field analysis, we establish superconducting order parameters in both the conventional Bardeen-Cooper-Schrieffer (BCS) and finite-momentum Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing channels. Intriguingly, both pairing states can support topological superconductivity, characterized by a nontrivial winding number, and lead to the emergence of four zero-energy Majorana modes localized at the ends of the 1D chain. The FFLO state further gives rise to an intrinsic field-free SDE, manifested as a nonreciprocal supercurrent and quantified by the diode efficiency $\eta$. Notably, our model yields a large diode efficiency $\eta \sim 65\%$, highlighting its potential for realising topological superconductivity and highly efficient superconducting devices.

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Amartya Pal, Debashish Mondal, Tanay Nag, Arijit Saha. 2025-12-01. Topological superconductivity and superconducting diode effect mediated via unconventional magnet and Ising spin-orbit coupling. https://doi.org/10.1103/g4ry-j1xy

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