Progress of Gate-Defined Semiconductor Spin Qubit: Host Materials and Device Geometries

Quantum computing offers the potential to revolutionize information processing by exploiting the principles of quantum mechanics. Among the diverse quantum bit (qubit) technologies, silicon-based semiconductor spin qubits have emerged as a promising contender due to their potential scalability and compatibility with existing semiconductor technologies. In this paper, the latest developments of spin qubits in gate-defined semiconducting nanostructures made of silicon and germanium, starting from the basic properties of electron and hole states in group-IV semiconductors, are reviewed. Specifically, various nanostructures that exploit their unique microscopic properties for qubit implementations, elaborating on the advances and challenges in experiments, are discussed. Strategies for enhancing qubit performance, such as designing new nanostructures and identifying suitable operating points, particularly those involving the valleys of electron qubits and the heavy-hole-light-hole mixing of hole qubits, are also highlighted. This comprehensive review thus provides valuable insights into the current state-of-the-art in semiconductor quantum computing and suggests avenues for future research. Silicon-based spin quantum bits (qubits) have emerged as a promising platform for large-scale quantum computing due to their compatibility with the semiconductor fabrication technology. This review covers the latest developments of spin qubits in various gate-defined semiconducting nanostructures made of silicon and germanium, and highlights strategies for enhancing qubit performance, such as designing new nanostructures and identifying suitable operating points.image