Weak-Field Magnetoresistance and the Valence-Band Structure of SnTe

Weak-field magnetoresistance measurements on $p$-type SnTe exhibit a peculiar symmetry which is temperature and carrier-concentration dependent. A Fermi-surface model is described which can account for these results and reconcile them with several other kinds of experimental measurements on SnTe. The Fermi surface consists of four prolate $〈111〉$ valleys with three $〈100〉$-oriented knobs protruding from each end of each valley. The proposed model is also used to bring out some previously unreported similarities between the band structures of the ${\mathrm{Pb}}_{1-x}{\mathrm{Sn}}_x\mathrm{Te}$ and ${\mathrm{Bi}}_{1-x}{\mathrm{Sb}}_x$ systems, and to examine the broader question of the connection between weak-field magnetoresistance behavior and band-structure characteristics.