Oral: Magnetic susceptibility of hexagonal boron nitride: the maximally localized Wannier function strategy

Magnetic susceptibility characterizes the response of a material's magnetization to an applied magnetic field, yet a comprehensive theoretical description of this fundamental property has proven challenging despite numerous attempts [1–8], and for a time, there was no true consensus in the literature [9]. Within the independent particle approximation, there are three contributions to the total susceptibility: Atomic diamagnetism, where local orbital electronic moments oppose the magnetic flux; Van Vleck paramagnetism, which accounts for the itinerant nature of electrons in a crystal; and a "geometric term" associated with the Brillouin zone manifold. Previously, we calculated the electronic magnetic susceptibility of hexagonal boron nitride (h-BN) using a two-band tight-binding model [9]. The geometric term, which requires breaking inversion symmetry, was the dominant contribution to the diamagnetic response. However, the contributions from the complete set of conduction bands are crucial for the geometric term and the Van Vleck paramagnetism. Here we calculate the magnetic susceptibility of h-BN, employing density functional theory and a basis of maximally localized Wannier functions; this allows for a careful treatment of the effects of the basis truncation and neglect of orbital overlap matrix elements on the magnetic susceptibility.