Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 84: Quantum Dots and Wires: Transport Properties III (mainly Thermal Gradients)
HL 84.3: Talk
Thursday, March 29, 2012, 15:30–15:45, EW 202
Thermal gradients and noise thermometry in 2D and 1D electron systems — •S.S. Buchholz1, E. Sternemann1, P. Miechowski1, D. Reuter2, A.D. Wieck2, and S.F. Fischer1 — 1Neue Materialien, Humboldt-Universität zu Berlin, D-10099 Berlin — 2Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44801 Bochum
Thermoelectric (TE) and out-of-equilibrium thermal properties of nanostructured semiconductors are of increasing research interest with respect to the improvement of the TE efficiency. A particular challenge is the determination of the charge carrier temperature at the nano-scale.
Here, we performed cross-correlated thermal voltage noise measurements under applied dc current heating in nanopatterned (2D and 1D) channels of a GaAs/AlGaAs heterostructure at bath temperatures of 1.4 K and above.
Via the current heating technique, we heat the electron system up to several K above the lattice temperature and measure the electron temperature by Nyquist-noise thermometry. In narrow 2D channels, the temperature dependence of the electron energy-loss rate is reduced compared to wider 2D systems [1], which may be attributed to the strong lateral confinement of the etched channels. In a 1D quantum interferometer sandwiched between a hot and a cold electron reservoir, we show the decoherence due to the diffusion of hot electrons by the thermal gradient.
[1] S.S. Buchholz et al., arXiv:1111.1591 (2011).