Spin noise spectroscopy of donor bound electrons in ZnO

TL;DR

This study uses optical spin noise spectroscopy to analyze the spin dynamics of electrons bound to Al impurities in ZnO, revealing hyperfine interactions and defect-related dephasing effects.

Contribution

It provides the first detailed measurement of spin relaxation times in donor-bound electrons in ZnO using spin noise spectroscopy, highlighting the influence of nuclear spins and defects.

Findings

Measured a spin dephasing time of 23 ns consistent with theory

Identified a high defect-related spin dephasing rate

Revealed the impact of nuclear and structural environment on electron spins

Abstract

We investigate the intrinsic spin dynamics of electrons bound to Al impurities in bulk ZnO by optical spin noise spectroscopy. Spin noise spectroscopy enables us to investigate the longitudinal and transverse spin relaxation time with respect to nuclear and external magnetic fields in a single spectrum. On one hand, the spin dynamic is dominated by the intrinsic hyperfine interaction with the nuclear spins of the naturally occurring $^{67}$Zn isotope. We measure a typical spin dephasing time of 23 ns in agreement with the expected theoretical values. On the other hand, we measure a third, very high spin dephasing rate which is attributed to a high defect density of the investigated ZnO material. Measurements of the spin dynamics under the influence of transverse as well as longitudinal external magnetic fields unambiguously reveal the intriguing connections of the electron spin with its nuclear and structural environment.