Theorem about spin splitting of energy levels within Kildal-Bondar model

Abstract

The semiconductor Cd₃As₂ is known as a zero-gap material like HgTe or α-Sn but with the tetragonal lattice and in various crystalline forms. One of the forms has no symmetry center, and just this form is stable under ordinary conditions. So, every of its energy bands is split into a pair of spin subbands owing to the removal of the Kramers degeneration. The theory predicts that the total sum of all spin splittings will be equal to zero, whereas the modeling shows the peculiar dependences of spin splittings on the direction and modulus of the wave vector.