X-ray Crystal Structure Analysis and Ru Valence of Ba4Ru3O10 Single Crystals

Taichi Igarashi (1) , Yoshio Nogami2 (2) , Yannick Klein (3) , Gwenaelle Rousse (3) , Ryuji Okazaki (1) , Hiroki Taniguchi (1) , Yukio Yasui (4) , Ichiro Terasaki (1)

1 Department of Physics [Nagoya]
2 Department of Physics, Okayama University
3 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
4 Department of Physics, Meiji University

We present a single-crystalline x-ray diffraction study on Ba4Ru3O10 consisting of corner-shared Ru3O12 trimers. The crystal structure is redetermined from 78 to 300K across an antiferromagnetic transition at 105 K. The orthorhombic symmetry (Cmca, space group No. 64) is preserved at all temperatures measured. This structure presents exceptionally long Ru-O distances characterized by a significant distribution within the Ru3O12 trimer. A bond valence sum calculation suggests that the charge disproportionation within the Ru3O12 trimer emerges even at room temperature, which we ascribe to molecular orbital formation in the Ru3O12 trimer, as supported by the results of recent theoretical calculations. On the basis of the analyzed crystal structure, the electronic states and the nature of the phase transition at 105K are discussed

Mots clés: X-ray diffraction; Ru oxide; antiferromagnetism; metal-insulator transition

Domaines: Physique Quantique [quant-ph]

Taichi Igarashi, Yoshio Nogami2, Yannick Klein, Gwenaelle Rousse, Ryuji Okazaki, et al.. X-ray Crystal Structure Analysis and Ru Valence of Ba4Ru3O10 Single Crystals. Journal of the Physical Society of Japan, 2013, 82, pp.104603. ⟨10.7566/JPSJ.82.104603⟩. ⟨hal-01056563⟩