Quantum Centers in Diamond

Diamond is a form of carbon that forms under high pressures. In addition to being admired for its beauty, it has long been used in industrial applications due to its hardness and thermal properties. At the turn of the century, it was noticed that diamond is also a good material for so-called quantum applications. Quantum mechanics describes how the physical world behaves at the scale of individual atoms and subatomic particles with many famous counter-intuitive predictions such as the wave particle duality and quantum superposition. Although all macroscopic materials are based on interactions arising from quantum mechanics, harnessing quantum phenomena for practical applications has remained challenging due to the fragility of quantum states. Diamond provides one solution to this problem due to its robustness and low number of naturally occurring imperfections in its structure. This allows detecting and manipulating quantum states related to impurity atom imperfections, which has lead to applications for example in sensor technology, medical imaging and quantum computing. QUEEN focuses on the study of the exact structure of such impurity-related imperfections and their manipulation through a combination of atomic-resolution transmission electron microscopy and various spectroscopic methods. Diamond structures will be further combined with the two - dimensional carbon material graphene for improved electronic properties. The results of the project will contribute to enabling new diamond-based quantum applications, as well as improving the performance of the already existing ones.

high pressures. In addition to its beauty, it has long been used in industrial applications for its hardness and thermal properties. At the turn of the century, it was noticed that diamond is also a good material for quantum applications. Quantum mechanics describes how the physical world behaves at the scale of individual atoms and subatomic particles, with many famous counterintuitive predictions such as the wave-particle duality and quantum superposition. Although all macroscopic materials are based on interactions arising from quantum mechanics, harnessing quantum phenomena for practical applications has remained challenging due to the fragility of quantum states. Diamond provides one solution to this problem due to its robustness and low number of naturally occurring imperfections in its structure. This allows detecting and manipulating quantum states related to impurity atom imperfections, so called quantum centres, which has lead to applications for example in sensor technology, medical imaging and quantum computing. Recently, it was observed that another material, hexagonal boron nitride, which has a layered structure similar to graphite, is also a good host for quantum centers. Interestingly, this material can be made atomically thin, into a 2D material, which provides a more direct access to the quantum centers, for example, through electron microscopy. QUEEN focused on studying the exact structure of these impurity-related imperfections and their manipulation using a combination of atomic-resolution transmission electron microscopy and spectroscopic methods. It was found that quantum centers in diamond are extremely mobile under electron microscopy, necessitating the development of new image analysis techniques that were subsequently applied to boron nitride and other systems with atomic-scale imperfections. As a result, the project benefited research far beyond its original scope. However, these unexpected dynamics made it harder to assess the exact atomic structures of quantum centers in diamond itself. Nevertheless, QUEEN has advanced the field by providing the first-ever direct images of quantum centers in diamond, spanning a wide range of elements and diamond types. It has also paved the way for new diamond-based quantum applications and the study of similar systems.