Effect of Ka-band Microwave on the spin dynamics of electrons in a GaAs/Al0.35Ga0.65As heterostructure

TL;DR

This study demonstrates that Ka-band microwave irradiation can significantly enhance the spin lifetime of electrons in a 2D GaAs/AlGaAs heterostructure, revealing potential for spintronic device applications.

Contribution

It provides experimental evidence of microwave-induced spin lifetime enhancement in 2D electron systems, a novel observation in spin dynamics research.

Findings

Microwave reduces spin lifetime in bulk GaAs near Zeeman resonance.

Microwave increases spin lifetime in 2D electron system from 745 ps to 1213 ps.

Enhanced spin lifetime attributed to microwave-induced electron scattering and motional narrowing.

Abstract

We report experimental results of the effect of Ka-band microwave on the spin dynamics of electrons in a 2D electron system in a GaAs/Al0.35Ga0.65As heterostructure, via time-resolved Kerr rotation measurements. While the microwave reduces the transverse spin lifetime of the bulk GaAs when its frequency is close to the Zeeman splitting of the electrons in the magnetic field, it significantly increases that of electrons in the 2D electron system, from 745 ps to 1213 ps. Such a microwave-enhanced spin lifetime is ascribed to the microwave-induced electron scattering which leads to a motional narrowing of spins via DP mechanism.