Quantum Defects

In the past decade point defects that introduces electronic states with optical transitions have garnered great interest as an important physical system for emergent quantum technologies [1], including quantum metrology, information processing and communications, as well as for nanotechnologies, such as biological imaging, and testing foundations of quantum mechanics. Initial focus was on defects in three-dimensional wide bandgap materials, such as diamond [2] and SiC [3]. Recently, color centers in layered two-dimensional materials such as hexagonal boron nitride hBN [4] have emerged as a promising candidate due to their enticing properties, such as high photostability, quantum yield, and brightness, even at room temperature. Moreover, 2D materials offer easier integration into complex photonic structures for on-chip quantum applications. Despite several studies [4-14] showing the potential of hBN color centers for quantum technologies, there remains a number of key questions that needs to be answered:

• What is the microscopic origin of single-photon emission in hBN and controlled synthesis of the color centers?
• Identification and rigorous characterization of color center’s atomic structure, spin multiplicity of the atomic states (ground, excited, and intermediate), etc.
• Electrical properties of these color centers, charge states, and their photoconversion process.
• Environmental effects (substrate, stress/strain, nearby spins, temperature, etc.) on the color center’s properties.

In this research, our initial focus is on addressing and answering these key questions through combined experimental, theoretical, and computational studies. We use single molecule methodologies to detect single color centers, high-resolution spectroscopic techniques to investigate the atomic structure of the defects, and photon-correlation measurements to assess their quantum nature.

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