LOMA, Université Bordeaux I, UMR 5798, F-33400 Talence, France.
J Phys Condens Matter. 2012 Jul 11;24(27):275701. doi: 10.1088/0953-8984/24/27/275701.
Superconducting correlations in an isolated metallic grain are governed by the interplay between two energy scales: the mean level spacing δ and the bulk pairing gap Δ0, which are strongly influenced by the position of the chemical potential with respect to the closest single-electron level. In turn superconducting correlations affect the position of the chemical potential. Within the parity projected BCS model we investigate the probability distribution of the chemical potential in a superconducting grain with randomly distributed single-electron levels. Taking into account statistical fluctuations of the chemical potential due to the pairing interaction, we find that such fluctuations have a significant impact on the critical level spacing δc at which the superconducting correlations cease: the critical ratio δc/Δ0 at which superconductivity disappears is found to be increased.
平均能级间距 δ 和体配对间隙 Δ0，它们受化学势相对于最近的单电子能级位置的强烈影响。反过来，超导相关性又会影响化学势的位置。在奇偶投影 BCS 模型中，我们研究了具有随机分布单电子能级的超导颗粒中化学势的概率分布。考虑到配对相互作用引起的化学势的统计涨落，我们发现这种涨落对超导相关性消失的临界能级间距 δc 有重大影响：发现超导消失的临界比 δc/Δ0 增大。
