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文摘
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Lattice, magnetic and orbital structures in KCuF_3 are self-consistently determined by our cluster self-consistent field approach based on a spin-orbital-lattice Hamiltonian. Two stable structures are obtained and found to be degenerate, which confirms the presence of the coexistent phases observed experimentally. We clearly show that due to the inherent frustration, the ground state of the system only with the superexchange interaction is degenerate; while the Jahn-Teller distortion, especially the anharmonic effect, stabilizes the orbital ordered phase at about 23% in the x~2-y~2 or bit and at 77% in the 3z~2-r~2 orbit. Meanwhile the magnetic moment of Cu is considerably reduced to 0.56μB, and magnetic coupling strengths are highly anisotropic, J_z/J_(xy)≈18.These resets are in good agreement with the experiments, implying that the anharmonic Jahn-Teller effect plays an essential role in stabilising the orbital ordered ground state of KCuF_3. |
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来源
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Chinese Physics. B
,2009,18(10):4497-4505 【核心库】
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DOI
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10.1088/1674-1056/18/10/066
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关键词
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orbital ordering
;
KCuF_3
;
Jahn-Teller effect
;
anharmonic lattice distortion
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地址
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Institute of Solid State Physics, Chinese Academy of Sciences, Key Laboratory of Materials Physics, CAS, Anhui, Hefei, 230031
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语种
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英文 |
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ISSN
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1674-1056 |
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学科
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物理学 |
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基金
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the '100 Talents Project' and the Knowledge Innovation Program of the Chinese Academy of Sciences
;
国家自然科学基金
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文献收藏号
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CSCD:3680960
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