London penetration depth in a tight-binding model of layered narrow-band anisotropic superconductors
- Faculty of Human Science, Tokiwa University, Mito, Ibaraki 310 (Japan)
The London magnetic penetration depth is investigated for the layered narrow tight-binding band anisotropic superconductors. The nearest-neighbor pairing interaction in planes and the tunneling between planes are assumed. The manifestly gauge-invariant expression for the static electromagnetic response kernel is derived within the framework of the ladder-diagram approximation. The out-of-plane penetration depth {lambda}{sub {perpendicular}}({ital T}) as well as the in-plane one {lambda}{sub {parallel}}({ital T}) is calculated as a function of hole density {ital n}{sub {ital h}} and temperature {ital T}({lt}{ital T}{sub {ital c}}). The resultant {lambda}{sub {perpendicular}}(0) and {lambda}{sub {parallel}}(0) depend symmetrically on hole and electron densities, and are almost not affected by the anisotropy of the order parameter. For both of the extended {ital s}-wave and {ital d}-wave states, the obtained anisotropy ratio {lambda}{sub {perpendicular}}(0)/{lambda}{sub {parallel}}(0) as well as {lambda}{sub {parallel}}(0) and {ital T}{sub {ital c}} can be in the range of the experimental results for high-{ital T}{sub {ital c}} superconductors. For the {ital d}-wave state, the resultant {lambda}{sub {perpendicular}}({ital T})/{lambda}{sub {perpendicular}}(0) as well as {lambda}{sub {parallel}}({ital T})/{lambda}{sub {parallel}}(0) has {ital T}-linear behavior at low temperature, and substantially deviates from those for the extended and usual {ital s}-wave states for all {ital T}{lt}{ital T}{sub {ital c}}. The in-plane and out-of-plane Ginzburg-Landau (GL) coherence lengths are also calculated by assuming their GL relations with the above penetration depths, and are compared with the experimental results. The case with the out-of-plane tunneling in proportion to carrier density is simply examined.
- OSTI ID:
- 44545
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 51, Issue 17; Other Information: PBD: 1 May 1995
- Country of Publication:
- United States
- Language:
- English
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