Spin-valley locking in Kekul\'e-distorted graphene with Dirac-Rashba interactions

TL;DR

This paper investigates how Kekul'e lattice distortions and Rashba spin-orbit coupling jointly influence graphene's electronic properties, revealing a new spin-valley locking effect and proposing experimental detection methods.

Contribution

It introduces a model integrating Rashba energy with Kekul'e distortions, uncovering a novel spin-valley locking term in the low-energy Dirac Hamiltonian for Kek-Y graphene.

Findings

Identification of a new spin-valley locking term in the Hamiltonian.

Analysis of low-energy band structure and Landau levels.

Proposal of an experimental scheme for detecting Rashba and Kekul'e effects.

Abstract

The joint effects of Kekul\'e lattice distortions and Rashba-type spin-orbit coupling on the electronic properties of graphene are explored. We modeled the position dependence of the Rashba energy term in a manner that allows its seamless integration into the scheme introduced by Gamayun et al.[New J. Phys. 20, 023016 (2018)] to describe graphene with Kekul\'e lattice distortion. Particularly for the Kekul\'e-Y texture, the effective low energy Dirac Hamiltonian contains a new spin-valley locking term, in addition to the well-known Rashba-induced momentum-pseudospin and spin-pseudospin couplings, and the Kekul\'e-induced momentum-valley coupling term. We report on the low-energy band structure and Landau level spectra of Rashba-spin-orbit-coupled Kek-Y graphene, and propose an experimental scheme to discern between the presence of Rashba spin-orbit coupling, Kek-Y lattice distortion, and both, based on doping-dependent magnetotransport measurements.