Impurity-induced virtual bound states in d-wave superconductors
Abstract
It is shown that a single, strongly scattering impurity produces a bound or a virtual-bound quasiparticle state inside the gap in a d-wave superconductor. The explicit form of the bound-state wave function is found to decay exponentially with angle-dependent range. These states provide a natural explanation of the second Cu NMR rate arising from the sites close to Zn impurities in the cuprates. Finally, for finite density of impurities in a d-wave superconductor, we re-examine the growth of these states into an impurity band, and discuss the Mott criterion for the metal-insulator transition in this band.
- Publication:
-
Physical Review B
- Pub Date:
- June 1995
- DOI:
- 10.1103/PhysRevB.51.15547
- arXiv:
- arXiv:cond-mat/9407102
- Bibcode:
- 1995PhRvB..5115547B
- Keywords:
-
- 74.10.+v;
- 71.27.+a;
- Occurrence potential candidates;
- Strongly correlated electron systems;
- heavy fermions;
- Condensed Matter
- E-Print:
- 12 pages and 2 figures, RevTex, LA-UR-94-1944