Long-lived electron spin coherence in Ga-doped crystals at room temperature

TL;DR

This study demonstrates long-lived electron spin coherence up to 5.2 ns at room temperature in Ga-doped ZnO crystals, revealing two distinct localized electron dephasing processes driven by anisotropic exchange interactions.

Contribution

It uncovers two types of localized electrons with long spin coherence times in Ga-doped ZnO at room temperature, driven by anisotropic exchange interactions.

Findings

Spin coherence time up to 5.2 ns at room temperature.

Long-lived spin signals originate from localized electrons.

Dephasing processes are independent of magnetic field inhomogeneity.

Abstract

Electron spin dynamics are studied in Ga-doped ZnO single crystals by time-resolved Faraday and Kerr rotation spectroscopies. Long-lived spin coherence with two dephasing processes is discovered where the characteristic time is up to 5.2 ns at room temperature. Through the dependence measurements of laser wavelength and temperature, the room-temperature long-lived spin signal is attributed to localized electrons. The spin dephasing (relaxation) processes are independent of transverse (longitudinal) magnetic fields, indicating the spin dephasing not resulting from the g-factor inhomogeneity and electron-nuclear hyperfine interaction. It reveals that the two spin dephasing processes originate from two types of localized electrons, both of which are dominated by the anisotropic exchange Dzyaloshinskii-Moriya interaction between adjacent localized electrons.