Use of ATM in evaluating spin-density

Because of its simplicity, the analytic tetrahedron method (ATM) of evaluating Brillouin zone integrals has become very popular. It has been used successfully in computing various properties, such as both electron and phonon density of states, optical conductivity, generalized susceptibility, and electric field gradients. Here it is used to compute the direct spin-density in sodium and potassium.