Oscillatory Magneto-Thermopower and Resonant Phonon Drag in a High-Mobility 2D Electron Gas

TL;DR

This paper reports experimental and theoretical evidence of low-magnetic-field oscillations in thermoelectric power of a high-mobility 2D electron gas, caused by resonant phonon interactions at specific magnetic fields.

Contribution

It introduces the observation of 1/B-oscillations in thermopower due to inter-Landau-Level phonon resonances, supported by numerical calculations including 3D and 2D phonons.

Findings

Observation of low-field 1/B-oscillations in thermopower.

Resonance condition involves phonons with momentum twice the Fermi wavenumber.

Both 3D and 2D phonons contribute to the effect.

Abstract

Experimental and theoretical evidence is presented for new low-magnetic-field ($B<5$ kG) 1/B-oscillations in the thermoelectric power of a high-mobility GaAs/AlGaAs two-dimensional (2D) electron gas. The oscillations result from inter-Landau-Level resonances of acoustic phonons carrying a momentum equal to twice the Fermi wavenumber at $B = 0$. Numerical calculations show that both 3D and 2D phonons can contribute to this effect.