Structural and electronic properties of molten semimetals: An ab initio study for liquid antimony

The structural and electronic properties of the crystalline semimetals As and Sb may be understood in terms of a Peierls distortion from the simple cubic structure bonds: as the (ppσ)-band is exactly half-filled, the cubic structure is unstable against dimerization dividing the six nearest-neighbour bonds into three strong and three weak bonds and opening a deep gap in the electronic density of states at the Fermi level. On the basis of neutron-diffraction experiments it has been suggested that some of the anomalous structural and electronic properties survive in the liquid phase. Here, an ab initio investigation of the structural, electronic, and dynamic properties of molten Sb that is based on the full set of quantum-many-body forces is presented. The results confirm the picture of a Peierls-distortion in the liquid.