Orbital angular momentum in a nonchiral topological superconductor

TL;DR

This paper studies the bulk orbital angular momentum in a 2D topological superconductor with Rashba spin-orbit coupling, revealing a crossover from s-wave to p-wave behavior and effects of impurities.

Contribution

It provides new insights into the orbital angular momentum behavior across topological phases in nonchiral superconductors with spin-orbit interaction.

Findings

Crossover from s-wave to p-wave before topological transition

Orbital angular momentum per electron does not reach -1/2 in the topological phase

Impurities influence the orbital angular momentum properties

Abstract

We investigate the bulk orbital angular momentum in a two-dimensional time-reversal broken topological superconductor with the Rashba spin-orbit interaction, the Zeeman interaction, and the $s$-wave pairing potential. Prior to the topological phase transition, we find the crossover from $s$ wave to $p$ wave. For the large spin-orbit interaction, even in the topological phase, $L_z/N$ does not reach $-1/2$, which is the intrinsic value in chiral $p$-wave superconductors. Here $L_z$ and $N$ are the bulk orbital angular momentum and the total number of electrons at zero temperature, respectively. Finally, we discuss the effects of nonmagnetic impurities.