Electrical control of spin coherence in ZnO

TL;DR

This study demonstrates that applying an electric field in ZnO significantly enhances electron spin coherence times at low temperatures, with effects linked to increased radiative recombination rates, independent of crystal orientation.

Contribution

It reveals a novel electric field method to control spin coherence in ZnO, showing a substantial increase in spin lifetime without altering the g-factor.

Findings

Electric field nearly doubles spin lifetime at 20 K

Enhancement persists at high temperatures but decreases with higher carrier density

Effects are independent of crystal orientation and magnetic field strength

Abstract

Electric field enhanced electron spin coherence is characterized using time-resolved Faraday rotation spectroscopy in n-type ZnO epilayers grown by molecular beam epitaxy. An in-plane dc electric field E almost doubles the transverse spin lifetime at 20 K, without affecting the effective g-factor. This effect persists till high temperatures, but decreases with increasing carrier concentration. Comparisons of the variations in the spin lifetime, the carrier recombination lifetime and photoluminescence lifetimes indicate that the applied E enhances the radiative recombination rate. All observed effects are independent of crystal directionality and are performed at low magnetic fields (B < 0.2 T).