Quantum Sensing with van der Waals Heterostructures based on hexagonal Boron Nitride

ongoing

The project idea is to implement a new quantum probe based on hexagonal boron nitride (hBN) containing spin defects to study the properties of artificially stacked two-dimensional (2D) materials and devices. The essential building blocks of such van der Waals (vdW) heterostructures are the quantum defects in hBN recently discovered by the PI and his team. These intrinsic lattice defects - negatively charged boron vacancies VB– - can be optically spin-polarized and coherently manipulated, allowing the read-out of quantum information during the coherence time. Our experimental approach is based on coherent manipulation of the spin state using high-frequency pulse protocols, followed by optical readout to explore the adjacent environment, in particular by studying the local lattice strains, pressure, temperature and magnetic fields. The unique feature of hBN is its non-disturbing chemical and crystallographic compatibility with other vdW materials, which gains a new fundamental functionality with the embedded spin centres and allows sensing in heterostructures serving as a boundary itself. Optical readout will be extended by electrical control of spin and charge states, which is an unexplored area and a major step forward in the development of quantum applications of vdW heterostructures. We focus on i) the enhancement of VB– emission and spin resonance contrast by coupling with plasmonic resonators to identify single defects never seen before, ii) the identification of the sources of spin decoherence of these defects, in particular the interaction with other electronic defects and hyperfine-coupled nuclear bath, and their bypassing, and iii) the exploration of semiconducting and magnetic heterostructures and electronic devices based on them. The project aims to establish 2D heterostructures as a flexible platform for new quantum applications based on the optical and electrical control of coherent states and mapping fluctuating external fields on the nanoscale.