中国物理B ›› 2020, Vol. 29 ›› Issue (6): 67702-067702.doi: 10.1088/1674-1056/ab84db

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

First-principles calculation of influences of La-doping on electronic structures of KNN lead-free ceramics

Ting Wang(王挺), Yan-Chen Fan(樊晏辰), Jie Xing(邢洁), Ze Xu(徐泽), Geng Li(李庚), Ke Wang(王轲), Jia-Gang Wu(吴家刚), Jian-Guo Zhu(朱建国)   

  1. 1 College of Materials Science and Engineering, Sichuan University, Chengdu 610064, China;
    2 School of Materials Science and Engineering, Beihang University, Beijing 100191, China;
    3 State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
  • 收稿日期:2020-02-20 修回日期:2020-03-26 出版日期:2020-06-05 发布日期:2020-06-05
  • 通讯作者: Ke Wang, Jian-Guo Zhu E-mail:wang-ke@tsinghua.edu.cn;nic0400@scu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51572143, 51822206, and 51932010).

First-principles calculation of influences of La-doping on electronic structures of KNN lead-free ceramics

Ting Wang(王挺)1,3, Yan-Chen Fan(樊晏辰)2, Jie Xing(邢洁)1, Ze Xu(徐泽)3, Geng Li(李庚)3, Ke Wang(王轲)3, Jia-Gang Wu(吴家刚)1, Jian-Guo Zhu(朱建国)1   

  1. 1 College of Materials Science and Engineering, Sichuan University, Chengdu 610064, China;
    2 School of Materials Science and Engineering, Beihang University, Beijing 100191, China;
    3 State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
  • Received:2020-02-20 Revised:2020-03-26 Online:2020-06-05 Published:2020-06-05
  • Contact: Ke Wang, Jian-Guo Zhu E-mail:wang-ke@tsinghua.edu.cn;nic0400@scu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51572143, 51822206, and 51932010).

摘要: The electronic structures of lead-free piezoceramic (K0.5Na0.5)NbO3 (KNN) and La-doped KNN ((K0.5Na0.5)0.994La0.006NbO3) are studied by using first principles calculation on the basis of density functional theory (DFT). The results reveale that the piezoelectricity stems from strong hybridization between the Nb atom and the O atom. At the same time, the K or Na atoms are replaced by the La doping atoms, which brings about the anisotropic relaxation. The La doping reduces the forbidden band, at the same time it makes Fermi surfaces shift toward the energetic conduction band (CB) of KNN. With the increase of La-doping intent, the phase structure of KNN extends from O-phase to T-phase and improves the piezoelectric properties of KNN.

关键词: (K0.5Na0.5)NbO3 (KNN), piezoelectricity, first-principles calculation, electronic structure

Abstract: The electronic structures of lead-free piezoceramic (K0.5Na0.5)NbO3 (KNN) and La-doped KNN ((K0.5Na0.5)0.994La0.006NbO3) are studied by using first principles calculation on the basis of density functional theory (DFT). The results reveale that the piezoelectricity stems from strong hybridization between the Nb atom and the O atom. At the same time, the K or Na atoms are replaced by the La doping atoms, which brings about the anisotropic relaxation. The La doping reduces the forbidden band, at the same time it makes Fermi surfaces shift toward the energetic conduction band (CB) of KNN. With the increase of La-doping intent, the phase structure of KNN extends from O-phase to T-phase and improves the piezoelectric properties of KNN.

Key words: (K0.5Na0.5)NbO3 (KNN), piezoelectricity, first-principles calculation, electronic structure

中图分类号:  (Ab initio calculations)

  • 31.15.A-
77.65.-j (Piezoelectricity and electromechanical effects) 77.84.Cg (PZT ceramics and other titanates)