1302.1054 (Baptiste Savoie)

On the atomic orbital magnetism: A rigorous derivation of the Larmor and
Van Vleck contributions    [PDF]

Baptiste Savoie

The aim of this paper is to rigorously investigate the orbital magnetism of core electrons in crystalline ordered solids and in the zero-temperature regime. To achieve that, we consider a non-interacting Fermi gas subjected to an external periodic potential within the framework of the tight-binding approximation (i.e. when the distance between two consecutive ions is large). For a fixed number of particles in the Wigner-Seitz cell and in the zero-temperature limit, we write down an asymptotic expansion for the bulk zero-field orbital susceptibility and prove that the leading term is the superposition of the Larmor diamagnetic contribution (reducing to the Langevin formula in the classical limit) together with the so-called orbital Van Vleck contribution.

View original: http://arxiv.org/abs/1302.1054