Ferromagnetic fluctuation and superconductivity in : FLEX study of multi-orbital Hubbard model

✍ Scribed by Masahito Mochizuki; Youichi Yanase; Masao Ogata

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 202 KB
• Volume: 359-361
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.01.161

✦ Synopsis

Spin and charge fluctuations and superconductivity in Na 0:35 CoO 2 Á 1:3H 2 O are studied based on a multi-orbital Hubbard model. By applying the fluctuation exchange (FLEX) approximation, we show that the Hund's-rule coupling between the Co t 2g orbitals causes ferromagnetic spin fluctuation. Triplet pairing is favored by this ferromagnetic fluctuation on the hole-pocket band. We propose that, in Na 0:35 CoO 2 Á 1:3H 2 O; Co t 2g orbitals and inter-orbital Hund's-rule coupling play important roles on the triplet pairing, and this compound can be a first example of the triplet superconductor mediated by inter-orbital interaction-induced ferromagnetic fluctuation.