Impact of Mn-O-O-Mn superexchange pathways in a honeycomb lattice Mn oxide with small charge-transfer energy

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• 作者：H. Wadati^a ; ^b ; ^{wadati@ap.t.u-tokyo.ac.jp} ; K. Kato^c ; Y. Wakisaka^c ; T. Sudayama^c ; D.G. Hawthorn^d ; T.Z. Regier^e ; N. Onishi^f ; M. Azuma^f ; Y. Shimakawa^f ; T. Mizokawa^c ; A. Tanaka^g ; G.A. Sawatzky^b
• 关键词：Bi3Mn4O12(NO3) ; Honeycomb lattice ; X-ray absorption spectroscopy ; Frustration
• 刊名：Solid State Communications
• 出版年：2013
• 出版时间：May, 2013
• 年：2013
• 卷：162
• 期：Complete
• 页码：18-22
• 全文大小：506 K

文摘

We investigated the electronic structure of layered Mn oxide Bi₃Mn₄O₁₂(NO₃) with a Mn honeycomb lattice by x-ray absorption spectroscopy and model calculations. The valence of Mn was determined to be with a small charge-transfer energy of 1 eV. The values of (J₁, J₂, J₃, J_c, J_c1, and J_c2) obtained by unrestricted Hartree-Fock calculations on Mn 3d-O 2p lattice models show that intra-layer second and third neighbor superexchange interactions J₂ and J₃ as well as inter-layer superexchange interactions J_c, J_c1, and J_c2 are enhanced due to Mn-O-O-Mn pathways, which are activated by the smallness of charge-transfer energy. The present analysis indicates that the ferromagnetic J_c1 and antiferromagnetic J_c2 are responsible to the antiferromagnetic inter-layer coupling and that the intra-layer exchange interactions with the ferromagnetic J₂ and antiferromagnetic J₃ have no frustration effect.