Self-excited Oscillations of Charge-Spin Accumulation Due to Single-electron Tunneling

TL;DR

This paper theoretically demonstrates that a quantum dot system with an inductor can exhibit self-sustained charge and spin oscillations at gigahertz frequencies due to Coulomb blockade and spin accumulation effects.

Contribution

It introduces a novel theoretical model showing how inductor inclusion leads to stable oscillations in charge and spin in quantum dot systems.

Findings

Oscillations occur at around 1 GHz frequency.

Steady transport can become unstable, leading to periodic oscillations.

A new stable regime with oscillating charge and spin is identified.

Abstract

We theoretically study electronic transport through a layer of quantum dots connecting two metallic leads. By the inclusion of an inductor in series with the junction, we show that steady electronic transport in such a system may be unstable with respect to temporal oscillations caused by an interplay between the Coulomb blockade of tunneling and spin accumulation in the dots. When this instability occurs, a new stable regime is reached, where the average spin and charge in the dots oscillate periodically in time. The frequency of these oscillations is typically of the order of 1GHz for realistic values of the junction parameters.