Tunable current circulation in triangular quantum-dot metastructures

¹ Theoretical Division, Los Alamos National Laboratory - Los Alamos, NM 87545, USA
² Center for Integrated Nanotechnologies, Los Alamos National Laboratory - Los Alamos, NM 87545, USA
³ Department of Physics, University of California, San Diego - La Jolla, CA 92093, USA
⁴ School of Natural Sciences, University of California, Merced - Merced, CA 95343, USA

Received: 29 March 2018
Accepted: 16 August 2018

Abstract

Advances in fabrication and control of quantum dots allow the realization of metastructures that may exhibit novel electrical transport phenomena. Here, we investigate the electrical current passing through one such metastructure, a system composed of quantum dots placed at the vertices of a triangle. The wave nature of quantum particles leads to internal current circulation within the metastructure in the absence of any external magnetic field. We uncover the relation between the metastructure steady-state total current and the internal circulation. By calculating the electronic correlations in quantum transport exactly, we present phase diagrams showing where different types of current circulation can be found as a function of the correlation strength and the coupling between the quantum dots. Finally, we show that the regimes of current circulation can be further enhanced or reduced depending on the local spatial distribution of the interactions, suggesting a single-particle scattering mechanism is at play even in the strongly correlated regime. We suggest experimental realizations of actual quantum-dot metastructures where our predictions can be directly tested.