Extended bound states and resonances of two fermions on a periodic lattice
Abstract
The high-Tc cuprates are possible candidates for d-wave superconductivity, with the Cooper pair wave function belonging to a nontrivial irreducible representation of the lattice point group. We argue that this d-wave symmetry is related to a special form of the fermionic kinetic energy and does not require any novel pairing mechanism. In this context, we present a detailed study of the bound states and resonances formed by two lattice fermions interacting via a nonretarded potential that is attractive for nearest neighbors but repulsive for other relative positions. In the case of strong binding, a pair formed by fermions on adjacent lattice sites can have a small effective mass, thereby implying a high condensation temperature. For a weakly bound state, a pair with nontrivial symmetry tends to be smaller in size than an s-wave pair. These and other findings are discussed in connection with the properties of high-Tc cuprate superconductors.
- Publication:
-
Physical Review B
- Pub Date:
- March 1997
- DOI:
- 10.1103/PhysRevB.55.6035
- arXiv:
- arXiv:supr-con/9608003
- Bibcode:
- 1997PhRvB..55.6035B
- Keywords:
-
- Condensed Matter - Superconductivity
- E-Print:
- 21 pages, RevTeX, 4 Postscript figures, arithmetic errors corrected. An abbreviated version (no appendix) appeared in PRB on March 1, 1997