Interplay of spin-orbit coupling and Coulomb interaction in ZnO-based electron system

TL;DR

This paper investigates how spin-orbit coupling interacts with Coulomb forces in a high-mobility ZnO-based 2D electron system, revealing tunable SOC effects influenced by electron-electron interactions, with implications for spintronics and novel quasiparticles.

Contribution

It demonstrates the emergence and tunability of spin-orbit coupling in a strongly interacting ZnO 2D electron system, highlighting the interplay between SOC and Coulomb interactions.

Findings

SOC strength can be tuned via carrier density adjustments.

Strong electron-electron interactions influence SOC effects.

Potential for emergent spintronic phenomena and novel quasiparticles.

Abstract

Spin-orbit coupling (SOC) is pivotal for various fundamental spin-dependent phenomena in solids and their technological applications. In semiconductors, these phenomena have been so far studied in relatively weak electron-electron interaction regimes, where the single electron picture holds. However, SOC can profoundly compete against Coulomb interaction, which could lead to the emergence of unconventional electronic phases. Since SOC depends on the electric field in the crystal including contributions of itinerant electrons, electron-electron interactions can modify this coupling. Here we demonstrate the emergence of SOC effect in a high-mobility two-dimensional electron system in a simple band structure MgZnO/ZnO semiconductor. This electron system features also strong electron-electron interaction effects. By changing the carrier density with Mg-content, we tune the SOC strength and achieve its interplay with electron-electron interaction. These systems pave a way to emergent spintronic phenomena in strong electron correlation regime and to the formation of novel quasiparticles with the electron spin strongly coupled to the density.