Week 2: Why electrons flow (two Fermi functions)

Why electrons flow: two Fermi functions (Datta Ch. 2)

Energy runs up the vertical axis, as in Datta's Fig. 2.4. Each contact tries to set the occupation of the channel states to its own Fermi function; current flows only where the two disagree, f₁(E) − f₂(E). The middle panel T(E) shows at which energies the channel can conduct: here one broadened level, standing in for Datta's D(E) (Chapter 3 makes this precise).

Channel:

Voltage V = (μ₁ − μ₂)/q Temperature T Level energy ε (relative to μ₀) Level broadening γ

Thermal energy kT–

Bias window μ₁−μ₂–

Current I (per mode)–

G = I/V–