Design of quantum defects | Qimin Yan Group

Discovery and design of quantum defects for quantum computing and information science

Like the classical bit that launched the modern electronic age, the quantum bit or qubit lies at the heart of the ongoing quantum information revolution that is expected to transform science and society in previously unimaginable ways. Although solid-state defects such as the diamond-NV centers in three-dimensional hosts have been demonstrated as promising qubits, atomically-thin two-dimensional (2D) materials offer an exciting new paradigm for qubit fabrication and operation at room temperature. Defects in 2D materials offer a new route to realize solid-state quantum computing, and the planar structures of these compounds provide a potentially superior platform for the realization of controlled generation and manipulation of defects as quantum qubits. Since 2018, my research has been supported by the DOE Quantum Information Science (QIS) program and an important context of the work is to understand the role of defects in 2D quantum materials for qubit technologies, where knowledge of defect formation, inter-state transitions, orbital symmetry and topology, light-matter interactions – quantities traditionally difficult to treat with DFT-based computations – is key for understanding and discovery.

Anion antisite defect qubits in transition metal dichalcogenides

Using a high-throughput materials discovery effort based on a novel defect-qubit design hypothesis, we identified anion-antisite defects in transition metal dichalcogenide (TMD) monolayers as viable spin qubits. This study opens a new pathway for creating scalable, room-temperature spin qubits in 2D TMDs and we believe that it presents a breakthrough in the field of solid-state quantum computing.

J.-Y. Tsai, J. Pan, H. Lin, A. Bansil, Q. Yan, “Antisite defect qubits in monolayer transition metal dichalcogenides”, Nat. Commun. 13, 492 (2022).

High-throughput discovery of quantum defects in 2D materials

The discovery of design principles for defect qubits will enable a large-scale high-throughput computational search for promising defect-based solid-state spin qubit systems. In the long term, this research can go beyond defect qubit systems and be extended to other quantum technologies such as quantum photonic systems including single-photon emitters and polarization-coupled entangled photon emitters.

J.-Y. Tsai, Q. Yan, “Perspective: Spin-Dependent Phenomena in Two-Dimensional Materials”. Phys. Chem. Chem. Phys. accepted (2021)