Regensburg 1998 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 4: Niedrigdimensionale Systeme, Magnetotransport und Quantenhalleffekt
TT 4.2: Vortrag
Montag, 23. März 1998, 15:00–15:15, H 19
Electron heating in diffusive metallic wires probed by noise thermometry — •M. Henny, C. Strunk, L. Lanz, H. Birk, R. Huber, and C. Schönenberger — Institut für Physik, Universität Basel, CH-4056 Basel
In mesoscopic wires even a small bias current can lead to a significant increase of the electron temperature Te above the bath temperature Tb. We determine the mean electron temperature ⟨ Te⟩ over the whole wire by measuring electric noise SI=4k⟨ Te⟩/R. Depending on the wire length L with respect to the electron-phonon scattering length le−ph, different temperature profiles along the wire are established. For shorter wires the influence of the reservoirs on the cooling of the electrons is studied [1].
For wires with L≫ le−ph, the electron temperature is nearly constant over the whole length and is directly related to the electron-phonon scattering time τe−ph. For three dimensions and in the clean limit one expects τe−ph−1∝ T3. In the presence of disorder, enhanced electron-phonon scattering is predicted by Schmid due to an increased coupling with transversal phonons. We have investigated different degrees of disorder by varying the film thickness. Significant deviations from the simple power law of the clean limit are observed and analysed in terms of the theory of Schmid [2].
[1] M. Henny et al., Appl. Phys. Lett. 71, 773 (1997).
[2] A. Schmid, in Localization, Interaction and Transport Phenomena, edited by B. Kramer, G. Bergmann and Y. Bruynseraede, (Springer, Berlin, 1985).