Magnetic fluctuation and pairing instability controlled by the CoO6 distortion in the sodium cobalt oxide
✍ Scribed by Masahito Mochizuki; Youichi Yanase; Masao Ogata
- Publisher
- Elsevier Science
- Year
- 2006
- Tongue
- English
- Weight
- 176 KB
- Volume
- 378-380
- Category
- Article
- ISSN
- 0921-4526
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✦ Synopsis
We study how the CoO 6 distortion along the c-axis affects the magnetic properties and superconductivity in the novel Co-oxide superconductor Na x CoO 2 Á yH 2 O by analyzing the multiorbital Hubbard model using the fluctuation-exchange approximation. It is shown that through generating the trigonal crystal field, the distortion pushes the Co e 0 g bands up and consequently gives rise to the holepocket Fermi surfaces, which have been predicted in the band calculations. As the distortion increases, the hole pockets are enlarged and the ferromagnetic fluctuation as well as the pairing instability increases, which is in good agreement with recent NQR results.