Intrinsic electronic defect states of anatase using density functional theory
Intrinsic electronic defect states of anatase using density functional theory
复制标题
使用密度泛函理论研究锐钛矿本征电子缺陷态
DOI：
10.1016/j.commatsci.2020.109925
复制
发表时间：
2020
影响因子：
3.3
通讯作者：
Panda Emila
中科院分区：
文献类型：
--
作者：
Raghav Abhishek;Tri Hanindriyo Adie;Utimula Keishu;Abbasnejad Mohaddeseh;Maezono Ryo;Panda Emila
在这项工作中的整体电子结构，包括各种本征缺陷的位置和形成能计算的Hubbard校正（DFT + U）辅助密度泛函理论。这里考虑的本征点缺陷是氧空位（VO）、氧间隙（Oi）、钛空位（VTi）和钛间隙（Tii）。在所有的本征缺陷中，VTi和Tii在平衡条件下是最稳定的。而TiO2的导带主要由Ti 3d态组成，并含有少量的O 2p态，价带主要由O 2p态组成，Ti 3d态的贡献也很小.发现VO和Ti在带隙中形成局域态。此外，在有效质量的各向异性。最后，利用平板超原胞计算得到的真空势作为参考，对所有本征缺陷态的能带图进行了排列。这一第一原理研究将有助于理解缺陷诱导的绝缘导电转变的光催化和光电领域，这将有重大影响。
In this work an overall electronic structure including the position and formation energies of various intrinsic defects are computed for anatase using Density Functional Theory aided by Hubbard correction (DFT + U). The intrinsic point defects considered here are, oxygen vacancy (VO), oxygen interstitial (Oi), titanium vacancy (VTi) and titanium interstitial (Tii). Out of all the intrinsic defects considered here, VTiand Tiiare found to be most stable under equilibrium condition. Whereas, conduction band in anatase is consisted of mainly Ti 3d with a minor component of O 2p states, valence band is found to be mainly composed of O 2p with a minor contribution from Ti 3d states. VOand Tiiare found to form localized states in the band gap. Moreover, anisotropy in the effective mass is seen. Finally, an alignment of band diagrams for all the intrinsic defect states is performed using vacuum potential from slab-supercell calculation as reference. This first principle study would help in the understanding of defect-induced insulating to conducting transition in anatase, which would have significant impact in the photocatalytic and optoelectronic area.