g-factor theory of Si/SiGe quantum dots: spin-valley and giant renormalization effects
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| Main Authors: | , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866915081632088064 |
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| author | Woods, Benjamin D. Losert, Merritt P. Joynt, Robert Friesen, Mark |
| author_facet | Woods, Benjamin D. Losert, Merritt P. Joynt, Robert Friesen, Mark |
| contents | 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 $\mathcal{O}(1)$, 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. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_19795 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | g-factor theory of Si/SiGe quantum dots: spin-valley and giant renormalization effects Woods, Benjamin D. Losert, Merritt P. Joynt, Robert Friesen, Mark Mesoscale and Nanoscale Physics Quantum Physics 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 $\mathcal{O}(1)$, 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. |
| title | g-factor theory of Si/SiGe quantum dots: spin-valley and giant renormalization effects |
| topic | Mesoscale and Nanoscale Physics Quantum Physics |
| url | https://arxiv.org/abs/2412.19795 |