Stochastization of long living spin-cyclotron excitations in a spin-unpolarised quantum Hall system

TL;DR

This paper investigates how long-lived spin-cyclotron excitations in a quantum Hall system become randomized over time due to phonon emission, revealing a nonexponential stochastization process and the resulting momentum distribution.

Contribution

It introduces a model for the nonexponential stochastization of spin-cyclotron excitations via phonon emission involving two excitons, highlighting a density-dependent emission rate.

Findings

Stochastization occurs nonexponentially over time.

Emission rate is proportional to the square of excitation density.

Final distribution differs from thermal equilibrium distribution.

Abstract

In the present study we address the kinetics of long-lived excitations at zero temperature in an electronic quantum Hall system with filling factor $\nu=2$. The initial coherent state of spin-cyclotron magnetoexitons with two-dimensional wave vector ${\bf q}=0$ resulting from laser pumping is stochastized over time due to emission of acoustic phonons. The elementary emission process requires participation of two magnetoexitons, so the effective rate of phonon emission is proportional to the excitation density squared, and the stochastization process occurs nonexponentially with time. The final distribution of magnetoexitons over 2D momenta, established as a result of stochastization, is compared with equilibrium distribution at finite temperature.