Determining energy relaxation length scales in two-dimensional electron gases
Applied Physics Letters
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Billiald, J., Backes, D., Farrer, I., Ritchie, D., Narayan, V., & König, J. (2015). Determining energy relaxation length scales in two-dimensional electron gases. Applied Physics Letters, 107 (022104)https://doi.org/10.1063/1.4926338
We present measurements of the energy relaxation length scale l in two-dimensional electron gases (2DEGs). A temperature gradient is established in the 2DEG by means of a heating current, and then the elevated electron temperature Te is estimated by measuring the resultant thermovoltage signal across a pair of deferentially biased bar-gates. We adapt a model by Rojek and König [Phys. Rev. B 90, 115403 (2014)] to analyse the thermovoltage signal and as a result extract l, Te, and the power-law exponent αi 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.
We acknowledge funding from the Leverhulme Trust, UK and the Engineering and Physical Sciences Research Council (EPSRC), UK.
External DOI: https://doi.org/10.1063/1.4926338
This record's URL: https://www.repository.cam.ac.uk/handle/1810/248862
Attribution-NonCommercial 2.0 UK: England & Wales
Licence URL: http://creativecommons.org/licenses/by-nc/2.0/uk/
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