  VOCl and other transition metal oxychlorides are candidate materials for
next-generation rechargeable batteries. We have investigated the influence of
the underlying magnetic order on the crystallographic and electronic structure
by means of density functional theory. Our study shows that antiferromagnetic
ordering explains the observed low-temperature monoclinic distortion of the
lattice, which leads to a decreased distance between antiferromagnetically
coupled V-V nearest neighbors. We also show that the existence of a local
magnetic moment removes the previously suggested degeneracy of the occupied
levels, in agreement with experiments. To describe the electronic structure, it
turns out crucial to take the correct magnetic ordering into account,
especially at elevated temperature.

Materials Science