Strain-induced exciton decomposition and anisotropic lifetime modulation in a GaAs micromechanical resonator

TL;DR

This study demonstrates how vibrational strain in a GaAs resonator modulates exciton lifetime through piezoelectric effects, revealing a new mechanism for controlling optomechanical interactions and thermal noise in solid-state systems.

Contribution

It introduces a novel method of modulating exciton lifetime via mechanical strain and elucidates the underlying piezoelectric and tunneling mechanisms involved.

Findings

Strain modulates exciton lifetime anisotropically.

Mechanical strain causes spatial separation of electrons and holes.

Exciton decay influences the resonator's thermal noise.

Abstract

We demonstrate mechanical modulations of the exciton lifetime by using vibrational strain of a gallium arsenide (GaAs) resonator. The strain-induced modulations have anisotropic dependences on the crystal orientation, which reveals the origin of these modulations to be the piezoelectric effect. Numerical analyses based on the tunneling model clarify that the mechanical strain modulates the internal electric field and spatially separates the electrons and holes, leading to non-radiative exciton decomposition. This carrier separation also generates an optomechanical back-action force from the photon to the resonator. Therefore, these results indicate that the mechanical motion can be self-modulated by exciton decays, which enables one to control the thermal noise of the resonators and provides a photon-exciton-phonon interaction in solid-state systems.