Weak antilocalization and zero-field electron spin splitting in AlGaN/AlN/GaN heterostructures with a polarization induced two-dimensional electron gas

TL;DR

This study investigates spin-orbit coupling in AlGaN/AlN/GaN heterostructures, revealing weak antilocalization effects and a linear relationship between electron spin splitting and Fermi wavevector, advancing understanding of spin dynamics in these materials.

Contribution

It provides the first detailed analysis of spin-orbit coupling and zero-field electron spin splitting in polarization-induced two-dimensional electron gases in these heterostructures.

Findings

Weak antilocalization observed with a spin-orbit field of ~1.8 mT.

Zero-field electron spin splitting scales linearly with Fermi wavevector.

Spin-orbit times range from 0.74 to 8.24 ps across carrier densities.

Abstract

Spin-orbit coupling is studied using the quantum interference corrections to conductance in AlGaN/AlN/GaN two-dimensional electron systems where the carrier density is controlled by the persistent photoconductivity effect. All the samples studied exhibit a weak antilocalization feature with a spin-orbit field of around 1.8 mT. The zero-field electron spin splitting energies extracted from the weak antilocalization measurements are found to scale linearly with the Fermi wavevector with an effective linear spin-orbit coupling parameter 5.5x10^{-13} eV m. The spin-orbit times extracted from our measurements varied from 0.74 to 8.24 ps within the carrier density range of this experiment.