Magnetotransport properties of an unconventional Rashba spin-orbit coupled two-dimensional electronic system

TL;DR

This paper investigates the unique magnetotransport phenomena in a 2D electronic system with unconventional Rashba spin-orbit coupling, revealing spin-polarized oscillations and Landau level crossings affecting quantum Hall effects.

Contribution

It provides analytical Landau level solutions and explores novel spin-dependent oscillations and Hall conductivity behaviors in an unconventional Rashba system.

Findings

Pure spin polarization of Shubnikov-de Haas oscillations achievable

Beating patterns in oscillations due to superposition of bands

Double jumps in Hall conductivity at Landau level crossings

Abstract

We study the magnetotransport properties of a two-dimensional electronic system with unconventional Rashba spin-orbit coupling in which the system is described by a pair of chiral spin texture in each spin branch, and the chirality is opposite in two spin branches. We obtain the Landau levels analytically and find that intra-spin and/or inter-spin Landau level crossing occurs. We compute the longitudinal conductivity and quantum Hall conductivity using the Kubo formalism based on linear response theory. We find that the usual Shubnikov-de Haas oscillation in longitudinal conductivity appears that can be made purely spin polarized by adjusting the Fermi level suitably. We observe a beating pattern in the Shubnikov-de Hass oscillation in the intra-spin branches, which arises due to the superposition of Shubnikov-de Hass oscillations corresponding to two bands in each spin branch. This is contrary to the conventional Rashba system, where such beating is due to the superposition of Shubnikov-de Hass oscillations corresponding to the two spin-branches. On the other hand, we note that quantum-Hall conductivity exhibits usual quantization in units of $e^2/h$ corresponding to each spin dependent Landau level. However, the Landau level crossing gives rise to the double jump in the Hall conductivity if the Fermi level is placed precisely at the crossing point.