Abstract
The superconducting order in an ultrasmall metallic grain with a fixed number of electrons is analyzed. By exploiting the intrinsic symmetries of the BCS Hamiltonian, we establish some general properties of a recently proposed pair-mixing correlation function on a mathematically rigorous basis. We also prove a relation between this function and the conventional off-diagonal correlation function. By variationally estimating both correlation functions, we show that the superconducting crossover in ultrasmall, metallic grains is smooth, a conclusion reached previously by numerical calculations.
Original language | English |
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Article number | 054511 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 63 |
Issue number | 5 |
DOIs | |
Publication status | Published - 10 Jan 2001 |
Scopus Subject Areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics