Modeling of surface magnetization
Cr2O3, an antiferromagnet with nonzero magnetoelectric multipole, has been found experimentally to possess a net surface magnetization density. However, a quantitative and qualitative description of the directions and magnitudes of the surface spins is still lacking.
Magnetoelectric multipoles describe variations in the magnetization density of a material beyond the basic magnetic dipole. While they are inherently bulk quantities, the values of these multipoles for a given compound should in fact directly determine the surface magnetization density, analogously to the intimate connection between bulk electric polarisation and surface charge. Using a combination of Density Functional Theory and Spin Dynamics simulations, I am interested in investigating the detailed behaviour of surface spins in materials with nonzero magnetoelectric multipoles, and connecting these theoretical results with experimental measurements of surface magnetization.