Bias-induced chiral current and topological blockadein triple quantum dots

TL;DR

This paper explores how bias can induce chiral currents and topological effects in a triple quantum dot system, revealing electrical control of chiral spin states and significant magnetoelectric responses.

Contribution

It demonstrates bias-induced chiral currents without magnetic fields and uncovers topological blockade phenomena in triple quantum dots, advancing quantum control techniques.

Findings

Bias induces chiral current oscillations within Coulomb blockade.

Topological blockade due to chiral state localization affects transport.

Magnetoelectric susceptibility is significantly enhanced at low temperatures.

Abstract

We theoretically investigate the quantum transport properties of a triangular triple quantum dot (TTQD) ring connected with two reservoirs by means of analytical derivation and accurate hierarchical-equations-of-motion calculation. A bias-induced chiral current in the absence of magnetic field is firstly demonstrated, which results from that the coupling between spin gauge field and spin current in the nonequilibrium TTQD induces a scalar spin chirality that lifts the chiral degeneracy and thus the time inversion symmetry. The chiral current is proved to oscillate with bias within the Coulomb blockade regime, which opens a possibility to control the chiral spin qubit by use of purely electrical manipulations. Then, a topological blockade of the transport current due to the localization of chiral states is elucidated by spectral function analysis. Finally, as a measurable character, the magnetoelectric susceptibility in our system is found about two orders of magnitude larger than that in a typical magnetoelectric material at low temperature.