Effect of p1/2 corrections in the electronic structure of Bi2Te3 compounds -: art. no. 155121

Unlike other relativistic corrections to the Schrodinger equation, such as the Darwin, mass-velocity, and spin-orbit interactions (SOI), the p(1/2) corrections do not arise from expansion of the relativistic Dirac equation. Rather, these corrections relate to the way in which the p-orbital wave functions are expanded in density functional calculations with SOI. A test of this correction is necessary in a strongly bonded system which has significant SOI effects, such as Bi2Te3. Previous electronic structure calculations of Bi2Te3 have disagreed about the position of the conduction band minimum (CBM). While de Haas-van Alphen experiments find the CBM to have sixfold degeneracy, most previous calculations have found this minimum to lie at a twofold degenerate point. A recent paper found the correct degeneracy, but was unable to explain the difference in their and previous results. We find the correct degeneracy by taking into account the p(1/2) corrections, which shifts the minimum from a twofold degenerate point to a sixfold degenerate point and is necessary for the correct degeneracy of the valence band as well. The p(1/2) corrections for the Sb 5p states are much weaker, explaining the electronic structure results in the related compounds Sb2Te3, Bi2Se3, and BiSbTe3.