Transferable tight-binding model for germanium

We present a transferable sp3s* tight-binding (TB) model for germanium within the first-nearest-neighbor interaction including both on-site and nearest-neighbor spin-orbit interactions. We have obtained TB parameters by optimizing the band structure and cohesive energy of Ge comparing with an ab-initio result. Our TB model produces the correct spin-orbit splitting and conduction band structure, which are very useful for studying the excited states.