Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 31: Matter at Low Temperature: Materials
TT 31.4: Vortrag
Mittwoch, 25. März 2009, 16:30–16:45, HSZ 304
Effect of the spin-orbit interaction on the thermodynamic properties of Bi and Sb — •Reinhard K. Kremer1, Manuel Cardona1, Luis E. Díaz-Sánchez2, Aldo H. Romero2, Xavier Gonze3, and Jorge Serrrano4 — 1Max Planck-Institut für Festkörperforschung, D-70569 Stuttgart, Germany — 2CINVESTAV, Departamento de Materiales, Unidad Querétaro, Querétaro, 76230, Mexico — 3Unité de Physico-Chimie et de Physique des Matériaux Université Catholique de Louvain B-1348 Louvain-la-Neuve, Belgium — 4ICREA-Dept. Física Aplicada, EPSC, Universitat Politécnica de Catalunya, Av. Canal Olímpic 15, 08860 Castelldefels, Spain
In the past years we have carried out a series of experiments as well as ab initio calculations of the dependence of the specific heat of semiconductors and insulators on T and isotopic masses. First results on the binary lead chalcogenides revealed marked differences between the calculated and the experimental heat capacities and the phonon dispersion relations. This finding raised the question of whether these discrepancies were due to the lack of spin-orbit (s-o) coupling in the ab initio electronic structure calculations. Using the ABINIT code which was recently extended to include s-o interaction we calculated the dispersion relations and the specific heat and compare it with our new low-temperature heat capacity measurements on Bi, Sb and PbX (X=S, Se, Te) and existing experimentally determined phonon dispersion relations. We find that agreement between measurements and calculations significantly improves when s-o interaction is included. Differences for the various investigated elements and binary systems are discussed.