Condensation Energy for a Two-Gap Superconducting State in Nanoparticles

Figure 2

Positioning of the chemical potential relative to the electronic energy levels in a two-gap superconducting grain. Solid and dotted lines mean two sublevels. (a) Half-filled system with 2𝑛₁+2𝑛₂ electrons, (b) 2𝑛₁+1+2𝑛₂-electron system, (c) 2(𝑛₁+1)+2𝑛₂-electron system, (d) 2(𝑛₁+1)+2𝑛₂+1-electron system, and (e) 2(𝑛₁+1)+2(𝑛₂+1)-electron system.

(a)

(b)

(c)

(d)

(e)