LINEAR-MUFFIN-TIN-ORBITAL CALCULATION OF TAC(001) SURFACE RELAXATION

Recent experimental work on the (001) surface of tantalum carbide has shown that this material is among the class of compounds which exhibit a marked rippling relaxation. We report here on a total-energy calculation of the relaxation of TaC(001), using a full-potential, linear-combination-of-muffin-tin-orbitals electronic-structure method. We obtain good agreement between calculated and experimental values for the degree of relaxation, and a detailed analysis of the physical mechanisms involved leads us to conclude that the nature of the rippled relaxation is determined primarily by the electrostatics associated with the bulk charge density. We also discuss other properties of the TaC(001) surface, including surface core-level shifts.