Half Metals with Simple Structures

Professor C. Y. Fong

Department of Physics
University of California, Davis, CA

Transition metal pnictides (group V), a carbide (group IV), their related superlattices with the zincblende structure, and several carbon quantum wires doped with transition metal elements were predicted to exhibit half metallic properties by the first-principles VASP code based on density functional theory and the generalized gradient approximation. MnAs serves as an example for the pnictides to explain the features of a half metal, the value of the magnetic moment/unit-cell and the interactions causing the half metallicity. MnC, a carbide, shows different half metallic properties from the pnictides. The physical implication of this difference will be presented. We will discuss half metallic superlattices made of pnictides including one of them exhibiting ballistic properties. Superlattices made of MnC and SiC will also be briefly commented on. Finally, we present a representative carbon quantum wire doped with Cr showing half metallic properties.