Atomic and electronic structures of charge-doping VO2: first-principles calculations

Abstract

The atomic and electronic structures of charge-doping VO₂ are investigated by using first-principles calculations. Hole doping is more conducive to stabilizing the structure of VO₂ than electron doping. The controllable phase transition temperature is coupled with changes in atomic and electronic structures. With the increase in hole density, the V–V chains and twisting angle experience a dramatic change, and the band gap (0.69–0 eV) is rapidly reduced due to orbital switching between the d_x²−y² and d_z²/d_yz orbitals. However, as the electron density increases, the band gap (0.69–0.502 eV) narrows slightly, while the V–O bond lengths significantly increase. The current results provide up a variable way to tune the VO₂ phase transition temperature through charge-doping.