Week 15: Coulomb blockade in Fock space

Coulomb blockade in Fock space (Datta Part B, Ch. 22, Figs. 22.1–22.9)

A two-level channel (spin up and down, both at ε = 0) with charging energy U₀. Left: the four Fock states 00, 01, 10, 11 and their steady-state probabilities for the chosen source level μ₁ (drain empty). Middle: the equilibrium n(μ), for one dot or for two coupled dots with entangled states. Right: current versus μ₁ for three models; the correct plateau is at 2/3, not 1/2.

Charging energy U₀ (eV) Temperature kT (meV) Source level μ₁ − ε (eV) Rate ratio ν₁/ν₂ Middle panel: system Inter-dot coupling t (eV), two dots

P(00) P(01)+P(10) P(11)–

I / I_max, Fock-space (exact)–

I / I_max, SCF U = U₀N–

I / I_max, non-interacting–