Current-induced effective Dzyaloshinskii–Moriya interaction and its Kondo enhancement in double quantum dot

Abstract

We studied the nonequilibrium transport of serially coupled double quantum dots connected to ferromagnetic electrodes. We demonstrated that the nonadiabatic part of the spin gauge field resulted in a current-induced Dzyaloshinskii–Moriya (DM) interaction effect in a double quantum dot and numerically confirmed this observation through the hierarchical equations of motion approach. We report that the spin current and the effective DM interaction are enhanced in the Kondo regime. We demonstrate that this enhancement occurs because the Kondo resonance, which is supposed to be suppressed by the local ferromagnetic exchange, is enhanced by the inter-dot coupling. This additional Kondo resonance channel increases the spin current. In addition, the impact of the spin–spin interaction and the Kondo effect on tunnel magnetoresistance is discussed. Our results offer a new approach for controlling the non-collinear spin interaction in double quantum dot devices.

Spin current Kondo effect in frustrated Kondo systems

“…Similarly, in a Mott insulator 22 or a nanoscale conducting ring coupled to ferromagnetic leads 23 , scalar chirality can induce circular electric currents. The correlation between spin vector chirality and electron spin current may be enhanced by the Kondo effect 24 . But how their strong coupling may affect the many-body ground state has not been explored.…”

Mechanism of current noise spectrum in a nonequilibirum Kondo dot system

“…The present study is based on the well-established dissipaton equation of motion (DEOM) approach [27][28][29][30][31]. This is a nonperturbative and accurate method, having been extensively explored in the study of quantum impurity problems [27,[32][33][34][35][36][37]. These include the recent noise spectrum evaluations, with the identification of Coulomb blockade assisted Rabi interference in a doubledot Aharonov-Bohm interferometer [37].…”