Core hole effect on topological band order in cubic semiconductors: A first-principles study

High-energy x-ray beams can excite the inner-shell electrons out of the sample and simultaneously leave behind core holes. Using first-principles calculations, we investigate the core hole effect on the topological band order in cubic semiconductors Ge and InSb. The band orders around the Fermi level are significantly changed by the presence of core holes, and consequently a topological phase transition from trivial to nontrivial states occurs with the increasing of the density of the core hole. Our work reveals an underlying relation between the core hole effect and the topological band order. It also provides a novel method for engineering three-dimensional topological insulators by optical means.