Abstract
Spin and charge fluctuations and superconductivity in Na xCoO2·yH2O are studied based on a multiorbital Hubbard model. Tight-binding parameters are determined to reproduce the results of band calculations. By applying the fluctuation-exchange approximation, we show that the Hund's-rule coupling between the Co t 2g orbitals causes ferromagnetic (FM) spin fluctuation. Triplet fy(y2-3x2)-wave and p-wave pairings are favored by this FM fluctuation on the hole-pocket band. We propose that, in NaxCoO 2·yH2O, the Co t2g orbitals and interorbital Hund's-rule coupling play important roles on the triplet pairing, and this compound can be a first example of the triplet superconductor in which the orbital degrees of freedom play substantial roles.
| Original language | English |
|---|---|
| Article number | 147005 |
| Journal | Physical Review Letters |
| Volume | 94 |
| Issue number | 14 |
| DOIs | |
| Publication status | Published - 2005 Apr 15 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
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Ferromagnetic fluctuation and possible triplet superconductivity in Na xCoO2·yH2O : Fluctuation-exchange study of the multiorbital hubbard model. / Mochizuki, Masahito; Yanase, Youichi; Ogata, Masao.
In: Physical Review Letters, Vol. 94, No. 14, 147005, 15.04.2005.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Ferromagnetic fluctuation and possible triplet superconductivity in Na xCoO2·yH2O
T2 - Fluctuation-exchange study of the multiorbital hubbard model
AU - Mochizuki, Masahito
AU - Yanase, Youichi
AU - Ogata, Masao
PY - 2005/4/15
Y1 - 2005/4/15
N2 - Spin and charge fluctuations and superconductivity in Na xCoO2·yH2O are studied based on a multiorbital Hubbard model. Tight-binding parameters are determined to reproduce the results of band calculations. By applying the fluctuation-exchange approximation, we show that the Hund's-rule coupling between the Co t 2g orbitals causes ferromagnetic (FM) spin fluctuation. Triplet fy(y2-3x2)-wave and p-wave pairings are favored by this FM fluctuation on the hole-pocket band. We propose that, in NaxCoO 2·yH2O, the Co t2g orbitals and interorbital Hund's-rule coupling play important roles on the triplet pairing, and this compound can be a first example of the triplet superconductor in which the orbital degrees of freedom play substantial roles.
AB - Spin and charge fluctuations and superconductivity in Na xCoO2·yH2O are studied based on a multiorbital Hubbard model. Tight-binding parameters are determined to reproduce the results of band calculations. By applying the fluctuation-exchange approximation, we show that the Hund's-rule coupling between the Co t 2g orbitals causes ferromagnetic (FM) spin fluctuation. Triplet fy(y2-3x2)-wave and p-wave pairings are favored by this FM fluctuation on the hole-pocket band. We propose that, in NaxCoO 2·yH2O, the Co t2g orbitals and interorbital Hund's-rule coupling play important roles on the triplet pairing, and this compound can be a first example of the triplet superconductor in which the orbital degrees of freedom play substantial roles.
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U2 - 10.1103/PhysRevLett.94.147005
DO - 10.1103/PhysRevLett.94.147005
M3 - Article
AN - SCOPUS:18244401933
VL - 94
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 14
M1 - 147005
ER -