Galvanomagnetic effects in antimony and doped antimony single crystals

Abstract

The twelve components of the magnetoresistivity tensor in antimony up to second order in magnetic field have been measured at 273ºK, 225ºK, 183ºK, 139ºK and 77ºK. Results are interpreted in terms of a two carrier, multi-valley band model to obtain carrier mobilities and densities as a function of temperature and details of the nature of the Fermi surface. In agreement with recent theoretical band structure calculations the electrons are shown to be sited in pockets with a small tilt angle (5º) away from the trigonal axis, while the extrema containing holes have a large tilt angle (24º). The temperature dependence of mobilities of electrons and holes are found to be T(^-1.42) and T(^-1.48) respectively. Carrier densities are almost independent of temperature, ranging from 3.9 x 10(^19) cm(^-3) at 77ºK to 4.2 x 10(^19) cm(^-3) at 273ºK for both electrons and holes. The Seebeck coefficient of antimony can be interpreted by inserting the mobility data obtained in a two parabolic band model. Results suggest that the Fermi energies are equal to 0.098 eV for electrons and 0.067 eV for holes giving a band overlap energy of 0.165 eV. These energy parameters are essentially temperature independent between 77ºK and room temperature, but increase markedly at higher temperatures. Holes probably occupy six and electrons three pockets. Conductivities, Hall coefficients and some of the magneto resistivity coefficients have been measured in t in - antimony alloys of compositions 1.7 at. % , 2.0 at. %, 2.5 at .% 3.0 at % and 8 at .% t in at 77 K, 183 K and 273 K to obtain further knowledge of the valence band structure. Results cannot be explained quantitatively by a simple tilted ellipsoidal band model, although they evidence that holes are to be assigned to the highly tilted ellipsoids.