Triangular Triple Quantum Dot: A Multiferroic Kondo System

Abstract

A triangular triple quantum dot (TTQD) is an artificial variant of an orbitally-degenerate atomic system, which is expected to exhibit a novel Kondo physics. We focus on the emergence of electric polarization by the Kondo effect, owing to electron hopping in the triangular loop that is triggered by a point contact between the apex of TTQD and a metallic lead. Since the charge distribution depends on the spin correlation in TTQD, the electric dipole can be controlled by applying a magnetic field that suppresses the Kondo effect. We demonstrate this multiferroic behavior on the nanoscale using an impurity Anderson model for the TTQD Kondo system.