Absorption of surface acoustic-waves by quantum dots: discrete spectrum limit

TL;DR

This paper investigates how surface acoustic waves are absorbed by quantum dots with discrete energy levels, revealing enhanced sensitivity to magnetic fields and spin-orbit effects, and proposing a new method to study energy relaxation and phase coherence.

Contribution

It provides a theoretical analysis of SAW absorption in quantum dots with discrete spectra, highlighting the increased sensitivity to magnetic and spin effects compared to continuous spectra.

Findings

Enhanced sensitivity to weak magnetic fields and spin-orbit scattering in discrete spectrum quantum dots.

Proposes non-invasive measurement of SAW attenuation as a tool to study energy relaxation and phase coherence.

Distinct behavior of SAW absorption in the discrete spectrum limit compared to continuous spectra.

Abstract

The absorption of surface acoustic waves (SAW's) by an array of quantum dots in which the mean level spacing Delta is larger than the sound frequency omega, the temperature T, and the phase breaking rate tau^{-1}_phi is considered. The direct and the intra-level (Debye) contributions to the SAW attenuation coefficient Gamma are evaluated, and it is shown that the sensitivity to weak magnetic fields and spin-orbit scattering (``weak localization effects'') is dramatically enhanced as compared to the case of a continuous spectrum, Delta < tau^{-1}_phi. It is argued that the non-invasive measurement of Gamma represents a new tool for the investigation of the temperature dependence of the energy relaxation rate, tau^{-1}_epsilon, and the phase breaking rate, tau^{-1}_phi$, of isolated electronic systems.