First-principles calculations of defect formation energy and carrier concentration of Ti4+, Ta5+ and W6+ doped KSr2Nb5O15

被引：9

作者：

Chen, Qian ^{[1
,2
]}

Zhang, Ruizhi ^{[2
,3
]}

Xu, Jie ^{[1
,2
]}

Cao, Shuyao ^{[1
,2
]}

Guo, Yiting ^{[1
,2
]}

Li, Yangping ^{[1
]}

Gao, Feng ^{[1
,2
]}

机构：

[1] Northwestern Polytech Univ, Sch Mat Sci & Engn, USI Inst Intelligence Mat & Struct, State Key Lab Solidificat Proc,MIIT Key Lab Radia, Xian 710072, Peoples R China

[2] Northwestern Polytech Univ, NPU QMUL Joint Res Inst Adv Mat & Struct, Xian 710072, Peoples R China

[3] Queen Mary Univ London, Sch Engn & Mat Sci, London E1 4NS, England

来源：

COMPUTATIONAL MATERIALS SCIENCE | 2020年 / 173卷

基金：

中国国家自然科学基金;

关键词：

Cation-doped KSr2Nb5O15; Formation enthalpy; Defect formation energy; Carrier concentration; Thermal properties; First-principles calculations; OPTICAL-PROPERTIES; DIELECTRIC-PROPERTIES; ELECTRONIC-STRUCTURE; STABILITY; CERAMICS; SRTIO3;

D O I：

10.1016/j.commatsci.2019.109427

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The formation enthalpy, chemical potential, defect formation energy and charge carrier concentration of Ti4+, Ta5+ and W6+ doped KSr2Nb5O15 (KSN-Ti, KSN-Ta and KSN-W) are obtained using first principles calculations for the purpose of predicting the influence of high valence cations on the structures and dielectric properties. It shows that when Ti4+, Ta5+ and W6+ doped into KSN, a phase transition from tetragonal to orthogonal occurs, where the KSN-Ti structure has a larger distortion than that of KSN-W, and KSN-Ta has the smallest lattice distortion. Both the band gap and the carrier concentration increase and of the trends are KSN-Ti > KSN-Ta > KSN-W and KSN-W > KSN-Ti > KSN-Ta, respectively. It is indicated that KSN-Ta is the most stable compound and KSN-Ti has the largest dielectric constant. The stability of KSN-Ti, KSN-Ta and KSN-W are in corresponding to the results of Gibbs energy that KSN-Ta < KSN-W < KSN-Ti, and the thermal expansion coefficient satisfies to KSN-Ta > KSN-W > KSN-Ti. This work paves the way to further understand the inner doping mechanism of cations and the method to improve dielectric properties of ferroelectric materials with tetragonal tungsten bronze structure like KSN.

引用

页数：13

共 49 条

[1] First-principles determination of chemical potentials and vacancy formation energies in PbTiO3 and BaTiO3 [J].