Dynamical multistability in a quantum-dot laser

TL;DR

This paper investigates the phenomenon of dynamical multistability in a quantum-dot laser system, revealing how spin-polarized currents induce multiple stable lasing states and how these states are reflected in charge current measurements.

Contribution

It demonstrates the emergence of multistable lasing in a quantum-dot spin valve due to the breakdown of the rotating-wave approximation at weak couplings.

Findings

Multistable lasing regimes with multi-peaked Fock distributions.

Charge current exhibits switching between distinct levels.

Multistability arises from breakdown of rotating-wave approximation.

Abstract

We study the dynamical multistability of a solid-state single-atom laser implemented in a quantum-dot spin valve. The system is formed by a resonator that interacts with a two-level system in a dot in contact with two ferromagnetic leads of antiparallel polarization. We show that a spin-polarized current provides high-efficiency pumping leading to regimes of multistable lasing, in which the Fock distribution of the oscillator displays a multi-peaked distribution. The emergence of multistable lasing follows from the breakdown of the usual rotating-wave approximation for the coherent spin-resonator interaction which occurs at relatively weak couplings. The multistability manifests itself directly in the charge current flowing through the dot, switching between distinct current levels corresponding to the different states of oscillation.