Determining energy relaxation length scales in two-dimensional electron gases

作者：Billiald Jordan^*; Backes Dirk; Koenig Juergen; Farrer Ian; Ritchie David; Narayan Vijay

来源：Applied Physics Letters, 2015, 107(2): 022104.

DOI：10.1063/1.4926338

We present measurements of the energy relaxation length scale in two-dimensional electron gases (2DEG5). A temperature gradient is established in the 2DEG by means of a heating current, and then the elevated electron temperature T-e is estimated by measuring the resultant thermovoltage signal across a pair of deferentially biased bar-gates. We adapt a model by Rojek and Konig [Phys. Rev. B 90, 115403 (2014)] to analyse the thermovoltage signal and as a result extract l, T-e, and the power-law exponent alpha(i) for inelastic scattering events in the 2DEG. We show that in high-mobility 2DEGs, l can attain macroscopic values of several hundred microns, but decreases rapidly as the carrier density n is decreased. Our work demonstrates a versatile low-temperature thermometry scheme, and the results provide important insights into heat transport mechanisms in low-dimensional systems and nanostructures. These insights will be vital for practical design considerations of future nanoelectronic circuits.

• 出版日期2015-7-13