Negative differential Rashba effect in two-dimensional hole systems

TL;DR

This paper reveals that in 2D heavy hole systems, increasing perpendicular electric field decreases spin splitting, contrasting with 2D electron systems where spin splitting increases with electric field.

Contribution

It provides the first experimental and theoretical demonstration of the negative differential Rashba effect in 2D hole systems, highlighting a novel behavior of spin-orbit interaction.

Findings

Spin splitting decreases with increasing electric field in 2D heavy hole systems.

Contrasts with the behavior of 2D electron systems.

Experimental and theoretical agreement on the negative differential Rashba effect.

Abstract

We demonstrate experimentally and theoretically that two-dimensional (2D) heavy hole systems in single heterostructures exhibit a \emph{decrease} in spin-orbit interaction-induced spin splitting with an increase in perpendicular electric field. Using front and back gates, we measure the spin splitting as a function of applied electric field while keeping the density constant. Our results are in contrast to the more familiar case of 2D electrons where spin splitting increases with electric field.