Theory of Spin Fluctuation-Induced Superconductivity Based on a d- p Model. II. —Superconducting State—
Abstract
The superconducting state of a two-dimensional d-p modelis studied from the spin fluctuation point of view by using a strong coupling theory. The fluctuation exchange (FLEX) approximatoin is employed to calculate the spin fluctuations and the superconducting gap functions self-consistently in the optimal- and over-doped regions of hole concentration. The gap function has a symmetry of dx2 - y2 type and develops below the transition temperature T c more rapidly than in the BCS model. Its saturation value at the maximum is about 10 k BT c. When the spin fluctuation-induced superconductivity is well stabilized at low temperatures in the optimal regime, the imaginary part of the antiferromagnetic spin susceptibility shows a very sharp resonance peak reminiscent of the 41 meV peak observed in the neutron scattering experiment on YBa2 Cu3 O7. The one-particle spectral density around k=(π,0) shows sharp quasi-particle peaks followed by dip and hump structures bearing resemblance to the features observed in the angle-resolved photoemission experiment. With increasing doping concentration these features gradually disappear.
- Publication:
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Journal of the Physical Society of Japan
- Pub Date:
- October 1998
- DOI:
- 10.1143/JPSJ.67.3570
- arXiv:
- arXiv:cond-mat/9806009
- Bibcode:
- 1998JPSJ...67.3570T
- Keywords:
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- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Superconductivity
- E-Print:
- 13 pages(LaTeX), 20 eps figures