摘要
基于密度泛函理论的第一性原理超软赝势平面波方法,研究静水压对CaCu_(3)Ti_(4)O_(12)(以下简称CCTO)能带结构、态密度及介电性能的影响,建立介电性能与晶胞畸变之间的内在关系。能带结构计算表明:价带顶主要由O-2p和Cu-3d态电子贡献,导带底主要由Ti-4d态电子贡献,且带隙随着压强的增加而增大;费米能级附近,O-2p态电子和Cu-3d态电子起主要作用,即CuO4正方形结构对CCTO的介电性能产生重要影响。介电性能分析表明:当压力不断增大时,CCTO晶格内原子间的相互距离,相互作用的强度和方式发生改变,促使电子结构发生变化,光频介电常数增大。因此,晶胞调控是优化CCTO介电性能的有效途径。
The effects of the hydrostatic pressures on the band structure,density of states,and dielectric properties of CaCu_(3)Ti_(4)O_(12)(CCTO in sort)are investigated with the plane wave psuedopetential method based on the first-principles of density functional theory,and the internal relationship between dielectric properties and lattice distortion are established.It is found that the top of the valence band is mainly determined by the orbital electrons of O-2p and Cu-3d,while the conduction band bottom is mainly determined by Ti-4d.At the same time,the band gap tends to increase with the hydrostatic pressures.Near the Fermi level,O-2p and Cu-3d play a major role;that is,CuO4 squares have an important influence on the dielectric properties of CCTO.Dielectric performance analysis shows that when the pressure continues to increase,the mutual distance between the atoms in the CCTO lattice decreases,and the strength and mode of interaction change is changed,prompting the change of electronic structure and the increase of optical frequency dielectric constant.Therefore,unit cell regulation is an effective way to optimize the dielectric properties of CCTO.
作者
王丹
成鹏飞
党子妍
WANG Dan;CHENG Pengfei;DANG Ziyan(School of Science, Xi’an Polytechnic University, Xi’an 710048,China)
出处
《西安工程大学学报》
CAS
2021年第1期102-107,共6页
Journal of Xi’an Polytechnic University
基金
国家自然科学基金(51277138)。
