Orbitally driven spin-singlet dimerization in S=1 La4Ru2O10

作者：Wu, Hua^*; Hu, Z.; Burnus, T.; Denlinger, J. D.; Khalifah, P. G.; Mandrus, D. G.; Jang, L. -Y.; Hsieh, H. H.; Tanaka, A.; Liang, K. S.; Allen, J. W.; Cava, R. J.; Khomskii, D. I.; Tjeng, L. H.

来源：Physical Review Letters, 2006, 96(25): 256402.

DOI：10.1103/PhysRevLett.96.256402

• TRANSITION-METAL OXIDES
• X-RAY-ABSORPTION
• HARTREE-FOCK
• PHOTOEMISSION
• SPECTRA
• CHARGE
• YVO3
• 3D

Using x-ray absorption spectroscopy at the Ru-L-2,L-3 edge we reveal that the Ru4+ ions remain in the S=1 spin state across the rare 4d-orbital ordering transition and spin-gap formation. We find using local spin density approximation+Hubbard U band structure calculations that the crystal fields in the low-temperature phase are not strong enough to stabilize the S=0 state. Instead, we identify a distinct orbital ordering with a significant anisotropy of the antiferromagnetic exchange couplings. We conclude that La4Ru2O10 appears to be a novel material in which the orbital physics drives the formation of spin-singlet dimers in a quasi-two-dimensional S=1 system.

• 出版日期2006-6-30
• 单位中国人民解放军国防大学