Ultra‐low acoustic‐phonon‐limited mobility and giant phonon‐drag thermopower in MgZnO/ZnO heterostructures
Year: 2013
Type: article
Abstract: We present numerical simulations of the acoustic‐phonon‐limited mobility, $ \mu _{\rm ac}, $ and phonon‐drag thermopower, S^{\rm g},$ in two‐dimensional electron gases confined in MgZnO/ZnO heterostructures. The calculations are based on the Boltzmann equation and are made for temperatures in the range 0.3–20 K and sheet densities 0.5–30 × 1015 m–2. The theoretical estimations of \mu _{\rm ac} $ are in good agreement with the experiment without any adjustable parameters. We find that the magnitude of \mu _{\rm ac} $ is dramatically decreased in relation to GaAs‐based heterostructures. The phonon‐drag thermopower, S^{\rm g},$ which according to Herring's expression is inversely proportional to \mu _{\rm ac} is severely increased exceeding 200 mV/K at T = 5 K depending on sheet density. The giant values of S^{\rm g} $ lead to a strong improvement of the figure of merit ZT at low temperatures. Our findings suggest that MgZnO/ZnO heterostructures can be candidates for good thermoelectric materials at cryogenic temperatures. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Author: Margarita Tsaousidou
Institution: University of Patras
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2048948525