A general and modular approach to solid-state integration and readout of zero-dimensional quantum systems

Electronic spectroscopy of zero-dimensional (0D) quantum systems, including point defects in solids, atomic states, and small molecules, is a critical tool for developing a fundamental understanding of these systems, with applications ranging from solid-state and molecular materials development to emerging technologies rooted in quantum information science. Toward this end, scanning tunneling spectroscopy (STS) has demonstrated atomic-scale sensitivity, but is not easily scalable for applications, whereas device-based approaches rely on embedding these systems within a solid-state tunnel junction (TJ) and are not generally applicable. Here we demonstrate an all-electrical readout mechanism for these quasi-0D states that is modular and general, dramatically expanding the phase space of accessible quantum systems and providing an approach that is amenable to scaling and integration with other solid-state quantum technologies. Our approach relies on the creation of high-quality tunnel junctions via the mechanical exfoliation and stacking of multi-layer graphene (MLG) and hexagonal boron nitride (hBN) to encapsulate the target quantum system (QS) in an MLG/hBN/QS/hBN/MLG heterostructure. This structure allows for electronic spectroscopy and readout of candidate quantum systems through a combination of Coulomb and spin-blockade, providing access to entire classes of quantum systems that have previously only been accessible via optical spectroscopy or magnetic resonance measurements of large ensembles, if at all.