Field-controlled spin and charge distributions in Kondo system with a triangular triple quantum dot

The Kondo effect plays an important role in the emergence of electric polarization in a triangular triple-quantum-dot system, where one of the three dots is connected to a metallic lead through a point contact. The interplay between spin and charge distributions is investigated on the basis of an impurity Anderson model where the impurity-site cluster is described by a three-site Hubbard model. The numerical renormalization group analysis demonstrates that an applied magnetic field suppresses the Kondo effect and that the three-site spin correlations lead to an abrupt change in the local electric and magnetic polarizations. The controllability of this multiferroic behavior on the nanoscale is also discussed.