Calculation of the electronic structure of antiferromagnetic chromium with a sinusoidal spin density wave by the method of dirac function linear combination

摘要

It has been found experimentally that, at temperatures below 312K, chromium has antiferromagnetic order with a spin density wave (SDW) incrommensurate with the lattice constant. The wave vector Q=2pi/alpha* (1-delta, 0,0) (a is the lattice constant and deltaapproxapprox0.05) of the SDW is oriented in the direction of one of the cubic axes. As a consequence the unit cell contains about 40 chemically equivalent atoms with different magnitude of the magnetic moment. The local magnetic moments are collinear and sinusoidally modulated with a maximum value M=0.59mu_B. At a temperature of 118K, the SDW polarization changes from longitudinal to transveral ( the spin-flip phase transition).