Manipulating the Charge State of Spin Defects in Hexagonal Boron Nitride.

Negatively charged boron vacancies (V) in hexagonal boron nitride (hBN) have recently gained interest as spin defects for quantum information processing and quantum sensing by a layered material. However, the boron vacancy can exist in a number of charge states in the hBN lattice, but only the -1 state has spin-dependent photoluminescence and acts as a spin-photon interface. Here, we investigate the charge state switching of V defects under laser and electron beam excitation. We demonstrate deterministic, reversible switching between the -1 and 0 states (V ⇌ V + e), occurring at rates controlled by excess electrons or holes injected into hBN by a layered heterostructure device. Our work provides a means to monitor and manipulate the V charge state, and to stabilize the -1 state which is a prerequisite for spin manipulation and optical readout of the defect.