First-principles study of phase-transition temperature and optical properties of alkaline earth metal (Be, Mg, Ca, Sr or Ba)-doped VO2

Abstract

Vanadium dioxide (VO2) is an attractive material for energy-saving smart windows due to its metal-to-insulator reversible phase transition near ambient temperature, accompanied by large changes in its optical properties. We conducted first-principles calculations to study the phase-transition temperature and optical properties of alkaline earth metal (Be, Mg, Ca, Sr or Ba)-doped VO2. The results show that the Be atom prefers to locate at the octahedral interstitial site, while Mg, Ca, Sr and Ba atoms prefer to substitute for the V atom in VO2. Be, Mg, Ca, Sr and Ba doping reduces the phase-transition temperature of VO2 0by 51.4, 59.7, 61.5, 58.4 and 58.3 K, respectively, when the doping concentration is set at one atomic percentage. In addition, the introduction of alkaline earth metal scales the band structures of VO2, which enhances the ability to block the infrared light (in the order of Be > Mg > Ca > Sr > Ba) and promotes the transmission of visible light (in the order of Be > Mg ≈ Ca > Sr > Ba).