Effect of proximity-induced spin-orbit coupling in graphene mesoscopic billiards

TL;DR

This paper investigates how proximity-induced spin-orbit coupling affects magnetoconductance in graphene-based mesoscopic devices, revealing robust weak antilocalization effects linked to symmetry-breaking at interfaces.

Contribution

It provides a theoretical and numerical analysis of spin-orbit effects in graphene heterostructures, highlighting the role of inversion symmetry breaking in quantum interference phenomena.

Findings

Robust weak antilocalization observed despite dominant symmetric spin-orbit coupling.

Interfacial inversion symmetry breaking crucial for quantum interference effects.

Transition from circular-orthogonal to circular-symplectic ensemble explained by random matrix theory.

Abstract

Van der Waals heterostructures based on two-dimensional materials have recently become a very active topic of research in spintronics, both aiming at a fundamental description of spin dephasing processes in nanostructures and as a potential element in spin-based information processing schemes. Here, we theoretically investigate the magnetoconductance of mesoscopic devices built from graphene proximity-coupled to a high spin-orbit coupling material. Through numerically exact tight-binding simulations, we show that the interfacial breaking of inversion symmetry generates robust weak antilocalization even when the $z\rightarrow -z$ symmetric spin-orbit coupling in the quantum dot dominates over the Bychkov--Rashba interaction. Our findings are in interpreted on the light of random matrix theory, which links the observed behavior of quantum interference corrections to a transition from circular-orthogonal to circular-sympletic ensemble.