Carrier Dynamics for the Collective Resonant Tunneling in Quantum Dot-Based Artificial Graphene

Abstract

Semiconductor quantum-dot (QD)-based artificial graphene (AG) is of great interest thanks to its innovative properties associated with the honeycomb topology, the many-body effects and the spin–orbit coupling of carriers, and its promising device applications. Considering the carrier variation in the real space of QDs besides the momentum space of AG, it is a big challenge to clarify the carrier dynamics that is the key feature and the base for device applications of QD-based AG. Here, the carrier dynamics for the collective resonant tunneling (CRT) of holes among QDs of AG is demonstrated. The current peak due to the CRT is affected by the voltage sweeping rate that modulates the number and the miniband width of holes in QDs of AG. The time-dependent conductance discloses three transport phases intimately associated with the number of holes in QDs of AG. Particularly, the CRT-induced high conductance phase is the figure of merit of AG. The phase transition and even the dual stable phases of transport can be realized by temporarily manipulating holes in QDs of AG via programmable voltages. Our results provide a guide to manipulate carriers in QD-based AG using an electric field to explore unique features and innovative devices of AG.