Dresden 2003 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Halbleiterphysik
HL 49: Poster II
HL 49.17: Poster
Donnerstag, 27. März 2003, 16:30–19:00, HSZ/P2
Thermoelectric Properties of Disordered Systems — •Rudolf A. Römer1, Angus MacKinnon2, and Cristine Villagonzalo3 — 1Department of Physics, University of Warwick, Coventry CV4 7AL, UK — 2Blackett Laboratory, Imperial College, London SW7 2BW, UK — 3National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101, Philippines
The electronic properties of disordered systems have been the subject of intense study for several decades. Thermoelectric properties, such as thermopower and thermal conductivity, have been relatively neglected. A long standing problem is represented by the sign of the thermoelectric power. In crystalline semiconductors this is related to the sign of the majority carriers, but in non-crystalline systems it is commonly observed to change sign at low temperatures. In spite of its apparent universality this change has been interpreted in a variety of ways in different systems. We have developed a Green’s function recursion algorithm [1] based on the Chester-Thellung-Kubo-Greenwood formula for calculating the kinetic coefficients Lij on long strips or bars. From these we can deduce the electrical conductivity σ, the Seebeck and Peltier coefficients S & Π and the thermal conductivity κ, as well as the Lorenz number L0. We present initial results for 1D, 2D and 3D systems. In 1D we observe a Lorentzian distribution for the thermopower which is modified by the presence of inelastic scattering. This could give rise to non-negligible quantum fluctuations in macroscopic systems at low temperatures.
[1] R. A. Römer, A. MacKinnon and C. Villagonzalo, accepted for publication in J. Phys. Soc. Japan, (2002)