Predicted semiconductor to metal transition from LiBSi2 to RbBSi2 by first-principles calculations

By means of the first-principles calculations, we performed a systematical investigation on the structure, electronic and mechanical properties of MBSi2 (M = Li, Na, K and Rb) and BSi2. The changes of lattice parameters and interatomic distance from BSi2 to RbBSi2 were discussed in detail. Both LiBSi2 and NaBSi2 with distorted sp(3) hybridization BSi2 three period networks are semiconductors, whereas KBSi2 and RbBSi2 with mixtures of sp(2) and sp(3) hybridization are metallic because of the weaker interaction in two-dimensional BSi2 net. Interestingly, a new BSi2 phase with no guest atom, featuring a metallic behavior, is predicted to be dynamically and mechanically stable. (C) 2016 Published by Elsevier B.V.