Sound and Heat Absorption by a 2D Electron Gas in an Odd-Integer Quantized-Hall Regime

Abstract

The absorption of bulk acoustic phonons in a two-dimensional (2D) GaAs/AlGaAs heterostructure is studied (in the clean limit) where the 2D electron-gas (2DEG), being in an odd-integer quantum-Hall state, is in fact a spin dielectric. Of the two channels of phonon absorption associated with excitation of spin waves, one, which is due to the spin-orbit (SO) coupling of electrons, involves a change of the spin state of the system and the other does not. We show that the phonon-absorption rate corresponding to the former channel (in the paper designated as the second absorption channel) is finite at zero temperature ($T$), whereas that corresponding to the latter (designated as the first channel) vanishes for $T\to 0$. The long-wavelength limit, being the special case of the first absorption channel, corresponds to sound (bulk and surface) attenuation by the 2DEG. At the same time, the ballistic phonon propagation and heat absorption are determined by both channels. The 2DEG overheat and the attendant spin-state change are found under the conditions of permanent nonequilibrium phonon pumping.

26 pages, 2 figures

References in corpus (3)

• Skyrme Crystal In A Two-Dimensional Electron Gas
• Surface acoustic wave attenuation by a two-dimensional electron gas in a strong magnetic field
• Skyrmion mass and a new kind of the cyclotron resonance for 2DEG

Cited by in corpus (6)

• The Cyclotron Spin-Flip Mode as the Lowest-Energy Excitation of Unpolarized Integer Quantum Hall States
• Zero-Momentum Cyclotron Spin-Flip Mode in a Spin-Unpolarized Quantum Hall System
• Competing Hyperfine and Spin-Orbit Couplings: Spin Relaxation in a Quantum Hall Ferromagnet
• Activation Energy in a Quantum Hall Ferromagnet and Non-Hartree-Fock Skyrmions
• Spin relaxation in a two-electron quantum dot
• Stochastization of long living spin-cyclotron excitations in a spin-unpolarised quantum Hall system