2024/12/27 by Benjamin D. Woods, Merritt P. Losert, Woods, Benjamin D. +5 · 3 citations
Physics and Astronomy · #Semiconductor Quantum Structures and Devices #Semiconductor materials and interfaces #Surface and Thin Film Phenomena
paper · doi:10.48550/arxiv.2412.19795
Understanding the g-factor physics of Si/SiGe quantum dots is crucial for realizing high-quality spin qubits. While previous work has explained some aspects of g-factor physics in idealized geometries, the results do not extend to general cases and they miss several important features. Here, we construct a theory that gives g in terms of readily computable matrix elements, and can be applied to all Si/SiGe heterostructures of current interest. As a concrete example, which currently has no g-factor understanding, we study the so-called wiggle well structure, containing Ge concentration oscillations inside the quantum well. Here we find a significant renormalization of the g factor compared to conventional Si/SiGe quantum wells. We also uncover a giant g-factor suppression of order O(1), which arises due to spin-valley coupling, and occurs at locations of low valley splitting. Our work therefore opens up new avenues for g-factor engineering in Si/SiGe quantum dots.