Evidence of phonon drag in the thermopower of a GaAs-<span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">Ga</mi></mrow><mrow><mn>0.68</mn></mrow></msub></mrow></math></span><span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">Al</mi></mrow><mrow><mn>0.32</mn></mrow></msub></mrow></math></span>As heterojunction

R. Fletcher; M. D’Iorio; A. S. Sachrajda; R. Stoner; C. T. Foxon; J. J. Harris

doi:10.1103/PhysRevB.37.3137

Rapid Communication

Evidence of phonon drag in the thermopower of a GaAs- ${Ga}_{0.68}$ ${Al}_{0.32}$ As heterojunction

R. Fletcher, M. D’Iorio, A. S. Sachrajda, R. Stoner, C. T. Foxon, and J. J. Harris

Phys. Rev. B 37, 3137(R) – Published 15 February 1988

Abstract

We report the first experimental demonstration that phonon drag is present in the thermopower of a two-dimensional electron gas at a GaAs- ${Ga}_{0.68}$ ${Al}_{0.32}$ As heterojunction in both zero and high magnetic fields. The experiment involves polishing the rear surface of the GaAs plate on which the junction is grown in order to increase the phonon mean free path. This results in an increase of the thermopower by about a factor of 2 even though the electrical resistivities are unaffected.