Longitudinal and transversal spin dynamics of donor-bound electrons in fluorine-doped ZnSe: spin inertia versus Hanle effect

TL;DR

This study investigates the spin dynamics of donor-bound electrons in fluorine-doped ZnSe, developing a spin inertia method to measure the long-lived $T_1$ relaxation time and analyzing dephasing times to understand relaxation mechanisms.

Contribution

A novel spin inertia technique is introduced to measure the $T_1$ relaxation time of donor-bound electrons across various conditions.

Findings

$T_1$ time is about 1.6 μs and remains constant across magnetic fields and temperatures.

Inhomogeneous dephasing time $T_2^*$ ranges from 8 to 33 ns.

Results restrict possible spin relaxation mechanisms in the material.

Abstract

The spin dynamics of the strongly localized, donor-bound electrons in fluorine-doped ZnSe epilayers is studied by pump-probe Kerr rotation techniques. A method exploiting the spin inertia is developed and used to measure the longitudinal spin relaxation time, $T_1$, in a wide range of magnetic fields, temperatures, and pump densities. The $T_1$ time of the donor-bound electron spin of about 1.6 $\mu$s remains nearly constant for external magnetic fields varied from zero up to 2.5 T (Faraday geometry) and in a temperature range $1.8-45$ K. The inhomogeneous spin dephasing time, $T_2^*=8-33$ ns, is measured using the resonant spin amplification and Hanle effects under pulsed and steady-state pumping, respectively. These findings impose severe restrictions on possible spin relaxation mechanisms.