Coulomb Blockade

Single-electron transport through a quantum dot
Stability diagram (Vg vs Vsd)
Conductance vs gate voltage
0.10
2.0
0.5
10.0
Coulomb blockade occurs when the charging energy E_C = e²/2C exceeds thermal energy k_BT. Adding a single electron costs E_C, blocking current. At special gate voltages, two charge states are degenerate — a Coulomb peak appears. The stability diagram shows "Coulomb diamonds" where conduction is blocked. Each diamond corresponds to a fixed integer electron number N.