Current-Induced Spin Polarization in Gallium Nitride

TL;DR

This study demonstrates current-induced spin polarization in bulk GaN using Kerr rotation spectroscopy, revealing spin polarization at temperatures up to 200 K despite weak spin-orbit coupling.

Contribution

First direct measurement of electrical spin polarization in bulk GaN across various doping levels and temperatures.

Findings

CISP observed up to 200 K in GaN.

Spin polarization characterized as a function of excitation energy.

Weak spin-orbit interactions still allow CISP in GaN.

Abstract

Electrically generated spin polarization is probed directly in bulk GaN using Kerr rotation spectroscopy. A series of n-type GaN epilayers are grown in the wurtzite phase both by molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD) with a variety of doping densities chosen to broadly modulate the transverse spin lifetime, T2*. The spin polarization is characterized as a function of electrical excitation energy over a range of temperatures. Despite weak spin-orbit interactions in GaN, a current-induced spin polarization (CISP) is observed in the material at temperatures of up to 200 K.