Determining the Rashba parameter from the bilinear magnetoresistance response in a two-dimensional electron gas

TL;DR

This paper presents a straightforward magnetotransport-based method to accurately determine the Rashba parameter in 2D electron gases, facilitating better characterization for spintronic device applications.

Contribution

It introduces a simple, quantitative approach to extract the Rashba parameter from angle-dependent magnetotransport measurements, avoiding complex spectroscopic techniques.

Findings

The method accurately yields the Rashba parameter across various Fermi energies.

Maximum Rashba effect observed at specific band structure regions with gate voltage.

Results align with theoretical predictions of interband effects enhancing Rashba coupling.

Abstract

Two-dimensional (2D) Rashba systems have been intensively studied in the last decade due to their unconventional physics, tunability capabilities, and potential for spin-charge interconversion when compared to conventional heavy metals. With the advent of a new generation of spin-based logic and memory devices, the search for Rashba systems with more robust and larger conversion efficiencies is expanding. Conventionally, demanding techniques such as angle- and spin-resolved photoemission spectroscopy are required to determine the Rashba parameter $\alpha_{R}$ that characterizes these systems. Here, we introduce a simple method that allows a quantitative extraction of $\alpha_{R}$, through the analysis of the bilinear response of angle-dependent magnetotransport experiments. This method is based on the modulation of the Rashba-split bands under a rotating in-plane magnetic field. We show that our method is able to correctly yield the value of $\alpha_{R}$ for a wide range of Fermi energies in the 2D electron gas at the LaAlO$_{3}$/SrTiO$_{3}$ interface. By applying a gate voltage, we observe a maximum $\alpha_{R}$ in the region of the band structure where interband effects maximize the Rashba effect, consistently with theoretical predictions.