四角晶相HfO2(001)表面原子和电子结构研究

采用基于第一性原理的密度泛函理论研究了四角晶相二氧化铪(t-HfO₂)体相及 其(001)表面的原子几何与电子结构.理论计算结果表明，t-HfO₂(001)表面不会 产生重构现象.与体相电子结构相比, t-HfO₂(001)表面态密度明显高于体相态 密度.其次，表面原子的态密度更靠近费米能级(E_F)，价带往低能量处移动，并 有表面态产生.计算结果表明了t-HfO₂表面禁带宽度明显低于体相的禁带宽度. t-HfO₂(001)的表面态产生以及表面禁带宽度减小是由于Hf原子与O原子的配位 数减少，表面原子周围的环境发生变化而引起的. 关键词： 密度泛函理论 2(001)')" href="#">t-HfO₂(001) 表面电子结构

Geometries and the electronic structures of t-HfO2 (001) surface

The geometries and the electronic structures of t-HfO₂ and its (001) surface have been studied by first-principle calculations using the density func tional theory (DFT). The optimized results show that the t-HfO₂ (001) surface has no surface reconstruction. Compared with the bulk electronic struct ure, the density of states (DOS) of t-HfO₂ (001) surface is higher th an that of the bulk. In addition, the DOS of t-HfO₂ (001) surface is closer to the Fermi level. The valence band has the tendency to move toward the lower energy, resulting in the formation of a new surface state. The band gap of t-HfO₂ (001) surface is much smaller than that of bulk band gap. The existence of a new surface state and the reduction of band gap are due to the r eduction of the Hf and O surface coordination which are different from the bulk atoms.