Spin-Orbital-Lattice Physics in Ca-Based Ruthenates
In this paper, we review some recent results, obtained by means of exact diagonalization technique, about the competition between the octahedral distortions and the Coulomb interactions for the t 2g electrons in layered Ca-based ruthenates. We provide a scenario where the flattening of the octahedra is the driving mechanism for yielding an antiferromagnetic state with C- or G-type structure and different orbital configurations. On the other hand, we show that the elongation of the octahedra gives rise to a ground state with incomplete ferromagnetism. To further account for unconventional spin-orbital configurations in the Ca2RuO4system, where all the t 2gdegrees of freedom contribute, the role of the spin-orbit coupling and its competition with compressed octahedral deformations are investigated. One of the main findings is the occurrence of anisotropic spin patterns with partially filled orbital occupation and coexisting ferro- and antiferro-type correlations in the spin/orbital channel.
KeywordsManifold Vanadate Lution Ferro Elon
Unable to display preview. Download preview PDF.
- 3. Y. Maeno, H. Hashimoto, K. Yoshida, S. Nishizaki, T. Fujita, J.G. Bednorz, F. Lichtenberg, Nature (London) 372, 532 (1994); Y. Maeno, T.M. Rice, M. Sigrist, Phys. Today 54, 42 (2001).Google Scholar
- 5. S. Nakatsuji, Y. Maeno, Phys. Rev. B 62, 6458 (2000); S. Nakatsuji, Y. Maeno, Phys. Rev. Lett. 84,2666(2000).Google Scholar
- 8.C.S. Alexander, G. Cao, V. Dobrosavljevic, S. McCall, J.E. Crow, E. Lochner, R.P. Guertin, Phys. Rev. B R8422R8425 (1999).Google Scholar
- 26. J. Jakli č , P. Prelovšek, Phys. Rev. B 49, 5065(R) (1994); J. Jakli č , P. Prelovšek, Adv. Phys. 49, 1(2000).Google Scholar