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TT: Tiefe Temperaturen

TT 22: Postersitzung III: Supraleitende Anwendungen (1-4) Massive HTSL, Bandleiter, Filme (5-26), Transport in HTSL (27-30), Elektronenstruktur in Supraleitern (31-43), Borkarbide (44-50), Quantenphasen- und Metall-Isolator-Überg
änge (51-69)

TT 22.63: Poster

Donnerstag, 30. März 2000, 14:00–17:30, A

The behavior of the thermopower in amorphous materials at the metal-insulator transition — •C. Villagonzalo, R.A. Römer, and M. Schreiber — Institut für Physik, Technische Universität, D-09107 Chemnitz

We use the linear response formulation of Ref. [1] in order to study the critical behavior of the thermopower at the metal-insulator transition (MIT) in experimentally relevant systems. We have taken the d.c. conductivity σ(T,s) data from Ref. [2] on stress-tuned Si:P as input for our calculations. Here T is the temperature and s is the dimensionless distance (e.g., stress or energy) from the critical point. Our preliminary investigation shows that the thermopower is two orders of magnitude less than the calculated values in the three dimensional Anderson model of localization [1]. These values are compatible with the experimental results. We also report on the temperature dependence of the thermal conductivity and the Lorenz number close to the MIT.

[1] C. Villagonzalo, R. A. Römer, and M. Schreiber, Eur. Phys. J. B 12, 179 (1999)

[2] S. Waffenschmidt, C. Pfleiderer, and H. v. Löhneysen, Phys. Rev. Lett. 83, 3005 (1999)