Proximity effects in two-dimensional transition-metal dichalcogenide materials for quantum information science

Significant strides have been made towards the storage and processing of quantum information. However, scalable robust material platforms are scarce. The two-dimensional (2D) transition-metal dichalcogenides provide a possible path forward due to their valley degrees of freedom, which may be probed by circularly polarized light. Unfortunately, these levels are commonly degenerate in energy. Therefore, to create a viable platform for valley-based qubits, it is crucial to break time reversal symmetry in a controllable manner, allowing for direct manipulation. Using state-of-the-art ab initio techniques, we demonstrate that controllable valley splitting can be achieved through a magnetic exchange proximity effect generated by a ferromagnetic 2D material substrate. Furthermore, by introducing vacancies into the transition-metal dichalcogenide layer, long-lived two-level impurity states may be stabilized. This approach reveals a new path towards the rational design of new complex multilayer systems for direct application in quantum information technologies and spin-optoelectronic devices.