Charging of quantum emitters in hexagonal boron nitride - graphene heterostructures due to electrostatic screening

TL;DR

This paper investigates how graphene encapsulation influences the charge states of defect centers in hexagonal boron nitride, revealing mechanisms for electrical control crucial for quantum technology applications.

Contribution

It demonstrates that electrostatic screening from graphene modifies defect charge levels and enables charge transfer and reorientation under moderate gate voltages.

Findings

Screening by graphene alters hBN defect charge levels

Charge transfer occurs due to encapsulation effects

Moderate gate voltages can reorient charged defects

Abstract

Defect color centers in hexagonal boron nitride (hBN) have gained significant interest as single-photon emitters and spin qubits for applications in a wide range of quantum technologies. As the integration of these solid-state quantum emitters into electronic devices necessitates electrical control, it is essential to gain a deeper understanding of the mechanisms of charge control for these defect color centers in hBN/graphene heterostructures. In this Letter, we show that screening due to the encapsulation of hBN with graphene modifies the electrical levels of hBN, leading to charge transfer. Furthermore, we show that the charged defects have low-energy barriers for defect reorientation which can be overcome by moderate gate voltages. This study shows that accurate modeling of the charge state of the defect is necessary to be able to electrically control defects.