Magnetic flux and gate-voltage dependence of Kondo effect in quantum dot embedded in Aharonov–Bohm ring

Abstract

The Kondo effect is examined in a quantum dot embedded in an Aharonov–Bohm (AB) ring, based on the Haldane's two-stage scaling theory. In the small limit of the ring size, we derive analytical expressions for the Kondo temperature T K and conductance at temperatures T ⪢ T K , as functions of the magnetic flux penetrating the ring. The flux dependence of T K is drastically changed when the energy level in the quantum dot is tuned electrostatically using the gate electrode attached to the dot. T K hardly depends on the flux at the midpoint in the Kondo valley of the Coulomb oscillation, whereas its flux dependence becomes remarkable apart from the midpoint.