Kondo Effect — Magnetic Impurity & Singlet Formation
Spin-flip scattering, resistivity minimum, and singlet formation below the Kondo temperature T_K
Parameters
Exchange coupling J·ρ:
0.15
Bandwidth D:
1.0
Impurity spin S:
0.5
Display:
Resistivity
Kondo temperature:
T_K = D·exp(-1/(J·ρ·S))
Resistivity:
ρ(T) = ρ₀[1 - J·ρ·ln(T/T_K)] + phonons
Minimum at T_min ~ T_K.
Below T_K:
conduction electrons screen impurity spin → singlet cloud of radius ξ_K ∝ v_F/T_K