First Observation of Noble Ferro-type Orbital States revealed by Resonant X-ray Scattering Interference Technique

In the contrast with many researches on orbital ordering in 3d and 4f electron systems, few studies were done on orbital ordering in 4d electron system so far. Among 4d electron systems, it is well known that Ca_2-xSr_xRuO₄ possesses the rich and novel ground states such as Mott transition accompanied with orbital ordering for x=0, heavy mass Fermi liquid behavior near the critical point for x=0.5, and the orbital degenerated triplet superconductivity for x=2.

Dr. Masato Kubota (Photon Factory/KEK) Prof. Youichi Murakami (Tohoku Univ.), Dr. Masaichiro Mizumaki (SPring-8/JASRI), Dr. Satoru Nakatsuji (Kyoto Univ.), and co-workers have successfully detected ferro-type orbital states in Ca_2-xSr_xRuO₄, by resonant x-ray scattering interference technique at the beamline BL46XU of SPring-8, which is the first observation in 4d Mott transition system. It is found that the underlying orbital dependent properties are the key to clarify complex phase diagram of Ca_2-xSr_xRuO₄.

Published in Physical Review Letters, 95, 026401 (2005). Masato Kubota, Youichi Murakami, Masaichiro Mizumaki, Hiroyuki Ohsumi, Naoshi Ikeda, Satoru Nakatsuji, Hideto Fukazawa, and Yoshiteru Maeno. "Ferro-type Orbital State in Mott Transition System Ca_2-xSr_xRuO₄ Studied by Resonant X-ray Scattering Interference Technique"

Source: Photon Factory/KEK, SPring-8