Strong Jahn-Teller effect at NiO4 tetrahedron in NiCo2O4 spinel

Dixing Ni; Shude Liu; Musheng Wu; Xueling Lei; Bo Xu; Seong Chan Jun; Chuying Ouyang

doi:10.1016/j.physleta.2019.126114

Strong Jahn-Teller effect at NiO₄ tetrahedron in NiCo₂O₄ spinel

Dixing Ni, Shude Liu, Musheng Wu, Xueling Lei, Bo Xu, Seong Chan Jun, Chuying Ouyang

Department of Mechanical Engineering

Research output: Contribution to journal › Article › peer-review

4 Citations (Scopus)

Abstract

The local structural distortion and electronic structure of the NiCo₂O₄ spinel are studied from first-principles calculations. It is found that very strong Jahn-Teller (J-T) distortion occurs to the NiO₄ tetrahedron and a large energy gain is obtained, leading to a substantial elongation of the lattice and a cubic to tetragonal phase transition. Further analysis shows that the Ni-3d states are split by not only the broken T_d symmetry of the NiO₄, chemical bonding interactions also exist between half-occupied d_yz and d_xz orbitals, which further lower the energy levels of the occupied d_yz and d_xz states in the spin-up channel. As a result, the energy gains from the J-T distortion are obtained to be 0.53 eV, 0.84 eV, and 0.83 eV per NiCo₂O₄ formula unit for using LDA, PBE and PW91 functionals, respectively.

Original language	English
Article number	126114
Journal	Physics Letters, Section A: General, Atomic and Solid State Physics
Volume	384
Issue number	4
DOIs	https://doi.org/10.1016/j.physleta.2019.126114
Publication status	Published - 2020 Feb 6

Bibliographical note

Funding Information:
This work is supported by the National Natural Science Foundation of China (NSFC, under Grant Nos. 51962010 and 11564016). The computations were partly performed on TianHe-2(A) at the National Supercomputer Center in Tianjin.

Funding Information:
This work is supported by the National Natural Science Foundation of China (NSFC, under Grant Nos. 51962010 and 11564016 ). The computations were partly performed on TianHe-2(A) at the National Supercomputer Center in Tianjin. Appendix A

Publisher Copyright:
© 2019 Elsevier B.V.

All Science Journal Classification (ASJC) codes

Physics and Astronomy(all)

Access to Document

10.1016/j.physleta.2019.126114

Cite this

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title = "Strong Jahn-Teller effect at NiO4 tetrahedron in NiCo2O4 spinel",

abstract = "The local structural distortion and electronic structure of the NiCo2O4 spinel are studied from first-principles calculations. It is found that very strong Jahn-Teller (J-T) distortion occurs to the NiO4 tetrahedron and a large energy gain is obtained, leading to a substantial elongation of the lattice and a cubic to tetragonal phase transition. Further analysis shows that the Ni-3d states are split by not only the broken Td symmetry of the NiO4, chemical bonding interactions also exist between half-occupied dyz and dxz orbitals, which further lower the energy levels of the occupied dyz and dxz states in the spin-up channel. As a result, the energy gains from the J-T distortion are obtained to be 0.53 eV, 0.84 eV, and 0.83 eV per NiCo2O4 formula unit for using LDA, PBE and PW91 functionals, respectively.",

author = "Dixing Ni and Shude Liu and Musheng Wu and Xueling Lei and Bo Xu and Jun, {Seong Chan} and Chuying Ouyang",

note = "Funding Information: This work is supported by the National Natural Science Foundation of China (NSFC, under Grant Nos. 51962010 and 11564016). The computations were partly performed on TianHe-2(A) at the National Supercomputer Center in Tianjin. Funding Information: This work is supported by the National Natural Science Foundation of China (NSFC, under Grant Nos. 51962010 and 11564016 ). The computations were partly performed on TianHe-2(A) at the National Supercomputer Center in Tianjin. Appendix A Publisher Copyright: {\textcopyright} 2019 Elsevier B.V.",

year = "2020",

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doi = "10.1016/j.physleta.2019.126114",

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T1 - Strong Jahn-Teller effect at NiO4 tetrahedron in NiCo2O4 spinel

AU - Ni, Dixing

AU - Liu, Shude

AU - Wu, Musheng

AU - Lei, Xueling

AU - Xu, Bo

AU - Jun, Seong Chan

AU - Ouyang, Chuying

N1 - Funding Information: This work is supported by the National Natural Science Foundation of China (NSFC, under Grant Nos. 51962010 and 11564016). The computations were partly performed on TianHe-2(A) at the National Supercomputer Center in Tianjin. Funding Information: This work is supported by the National Natural Science Foundation of China (NSFC, under Grant Nos. 51962010 and 11564016 ). The computations were partly performed on TianHe-2(A) at the National Supercomputer Center in Tianjin. Appendix A Publisher Copyright: © 2019 Elsevier B.V.

PY - 2020/2/6

Y1 - 2020/2/6

N2 - The local structural distortion and electronic structure of the NiCo2O4 spinel are studied from first-principles calculations. It is found that very strong Jahn-Teller (J-T) distortion occurs to the NiO4 tetrahedron and a large energy gain is obtained, leading to a substantial elongation of the lattice and a cubic to tetragonal phase transition. Further analysis shows that the Ni-3d states are split by not only the broken Td symmetry of the NiO4, chemical bonding interactions also exist between half-occupied dyz and dxz orbitals, which further lower the energy levels of the occupied dyz and dxz states in the spin-up channel. As a result, the energy gains from the J-T distortion are obtained to be 0.53 eV, 0.84 eV, and 0.83 eV per NiCo2O4 formula unit for using LDA, PBE and PW91 functionals, respectively.

AB - The local structural distortion and electronic structure of the NiCo2O4 spinel are studied from first-principles calculations. It is found that very strong Jahn-Teller (J-T) distortion occurs to the NiO4 tetrahedron and a large energy gain is obtained, leading to a substantial elongation of the lattice and a cubic to tetragonal phase transition. Further analysis shows that the Ni-3d states are split by not only the broken Td symmetry of the NiO4, chemical bonding interactions also exist between half-occupied dyz and dxz orbitals, which further lower the energy levels of the occupied dyz and dxz states in the spin-up channel. As a result, the energy gains from the J-T distortion are obtained to be 0.53 eV, 0.84 eV, and 0.83 eV per NiCo2O4 formula unit for using LDA, PBE and PW91 functionals, respectively.

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