Relativistic band structure calculations

The inclusion of relativistic effects in band theory is discussed. Examples showing how these affect optical properties, Fermi surface properties, and cohesive properties are shown. With respect to the latter, it is pointed out that the mass–velocity and Darwin shifts are most important, whereas the SO coupling can be omitted since it does not shift the bands (quenching of angular momentum). The band theoretical aspects are presented in the terminology of the LMTO -ASA method which offers a physical transparent picture of the formation of bands. The volume and energy dependences of the spin-orbit splittings are explained in this picture. As examples are considered calculations for W, Xe, Au, and the copper halides.