Pientka, Falko; Gradhand, M.; Fedorov, D.V.; Mertig, I.; Györffy, B.L.
Year of publication:
In nonmagnetic crystals with inversion symmetry the electronic bands are
twofold degenerate. As a consequence, any orthonormalized linear combination
of the two corresponding eigenfunctions can represent the electron wave
function. A priori it is not obvious which superposition, gauge, should be
chosen to calculate a quantity which is not gauge invariant within a certain
approximation. Here we consider gauge options appropriate under particular