“Two-Stage Kondo Effect”

Dr. Mikhail Kiselev
The Abdus Salam International Centre
for Theoretical Physics (ICTP)

Sep. 10 (Tue.), 03:00 PM
E6-2. 1st fl. #1323

Abstract:
We consider a quantum dot with K>1 orbital levels occupied by two electrons connected to two electric terminals. The generic model is given by a multilevel Anderson Hamiltonian. The weak-coupling theory at the particle-hole symmetric point is governed by a two-channel S=1 Kondo model characterized by intrinsic channels asymmetry. Based on a conformal field theory approach we derived an effective Hamiltonian at a strong-coupling fixed point. The Hamiltonian capturing the low-energy physics of a two-stage Kondo screening represents the quantum impurity by a two-color local Fermi liquid. Using non-equilibrium (Keldysh) perturbation theory around the strong coupling fixed point we analyze the transport properties of the model at finite temperature, Zeeman magnetic field, and source-drain voltage applied across the quantum dot. We compute the Fermi-liquid transport constants and discuss different universality classes associated with emergent symmetries.