Effective nodal topological superconductivity driven by s-wave pairing and the ferromagnetic proximity effect in materials with persistent spin textures

Abstract

Nodal topological superconductivity (NTSC) with flat Majorana boundary modes connecting gapless nodal points represents a nontrivial superconductivity (SC) phase capable of fault-tolerant topological quantum computing. In addition to unconventional SC with nodal pairing gap, two-dimensional (2D) NTSC has been effectively achieved from conventional s-wave SC by applying a magnetic field to symmetry-protected out-of-plane persistent spin texture (PST). Here we demonstrate that the effective NTSC can be alternatively achieved from in-plane PST under the ferromagnetic proximity effect, where the gapless nodal points within the SC gap remain robust at the entire energy range of the PST-enforced nodal line electronic states. This discovery positions (110)-oriented GaAs/AlGaAs and InAlAs/InGaAs quantum wells with extrinsic in-plane PST as ready-made NTSC platforms. Meanwhile, we propose that intrinsic in-plane PST is available in 2D stoichiometric materials with C2v or D2 point group symmetry by balancing different antisymmetric spin-orbit coupling effects. Our first-principles calculations indicate the balance is readily struck in monolayer XThBr6 (X=Ca, Sr, Ba) with C2v symmetry, while D2 symmetry enforced in-plane PST is identified in AuO2Br and CuO2F monolayers. This work not only expands the theoretical framework of effective NTSC, enabling its implementation in experimentally prepared quantum wells, but it also introduces a feasible route to achieve intrinsic in-plane PST in 2D stoichiometric compounds for device miniaturization.

Source-reported materials — not catalogue approval

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