| Coulomb charging energy of a metallic dot |
| E = Q2/
2 SC |
| Where SC total
capacitance coupling the dot to external conductors. |
| For SC=10-5
cm » 10-5 pF and Q=e: |
| E= 100 K |
| Device must be
cold and/or small! |
| And weakly
coupled to the external reservoirs. |