First-Principles Study of Electronic Structure of Orthorhombic SrHfO3 under Pressure

摘要:

采用第一性原理研究了压力对正交相SrHfO3电子结构的影响。正交相SrHfO3在零压力时的结构参数与已有的实验值和理论计算值一致。当施加的压力小于20 GPa时，正交相SrHfO3 的最小间接带隙在Z-Γ之间。当施加的压力大于20 GPa时，正交相SrHfO3的最小间接带隙在S-Γ之间。随着压力的增加，正交相SrHfO3的态密度向低能量方向移动。电荷密度分析表明，Hf-O之间主要以共价键结合，Sr-O之间主要以离子键结合。随着压力的增加，Hf-O共价键和Sr-O离子键增强, 而Sr-HfO3之间的离子交互作用减弱

Abstract:

First-principles calculations were performed to investigate electronic structure of orthorhombic SrHfO3 under pressure. The optimized lattice parameters of the orthorhombic SrHfO3 at zero pressure are in very good agreement with the available experimental and calculational values. The pressure dependence of band structure, density of states (DOS) and charge densities of orthorhombic SrHfO3 was obtained. When pressure is low (<20 GPa) the minimum indirect band gap of the orthorhombic SrHfO3 is Z-Γ while it is changed to be S-Γ when pressure is high (≥20 GPa). With the increase of pressure, the DOS of orthorhombic SrHfO3 shifts to the lower energy. Charge densities imply that bonding between Hf and O is mainly a covalent bonding and the bonding between Sr and O is mainly an ionic bonding. With the increasing of pressure, the covalent bonding (Hf-O) and the ionic bonding (Sr-O) are enhanced, whereas the ionic interactions (Sr-HfO3) are weakened