First Principle Search of Quantum Point Defects
Quantum-enhanced technologies, including quantum computing, communication, and sensing, augment the capabilities of classical technology by leveraging the unique properties of quantum physics. These technologies can solve problems intractable to conventional computers, establish fundamentally secure communication, and build nanoscale sensors. Qubit (quantum bit), a two-level quantum system, is the fundamental building block of these quantum devices. For the quantum system to qualify as a qubit, its coherence time must be long enough to permit the operation of quantum gates with high fidelity. The superposition state of the quantum system must be isolated from environmental noise to ensure a long coherence time. Different material platforms, such as solid defects, atoms in an optical lattice, trapped ions, nuclear spin, superconducting circuits, and spins in semiconducting quantum dots, are capable of hosting qubits [1]. Superconducting Josephson junction, the leading candidate in the race to build a quantum computer, requires the cryogenic temperature to protect the quantum superposition. However, defect protected by the wide bandgap of semiconductors is demonstrated to operate even at room temperature. In addition to quantum information processing, quantum defects provide attractive features for single photon emission and quantum-enhanced sensing applications [1]. Identifying quantum defects suitable for specific applications is the first step in developing solid-state based quantum technologies.
We use first principle Density functional theory to model point defect in solids to understand the thermodynamic, electronic, optical and magnetic properties. Based on the first principle investigation, we identify potential defect for different quantum application.
References
- Gang Zhang, Yuan Cheng, Jyh-Pin Chou, and Adam Gali. Material platforms for defect qubits and single-photon emitters. Applied Physics Reviews, 7(3):031308, September 2020.