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| Format: | Preprint |
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2026
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| Online Access: | https://arxiv.org/abs/2605.16947 |
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| _version_ | 1866911690977705984 |
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| author | Prabhakar, Sanjay |
| author_facet | Prabhakar, Sanjay |
| contents | Controlling electron spins in double quantum dots allows individual electrons to be trapped and manipulated for next-generation solid-state qubit devices. In this paper, the study analyzes spin relaxation due to deformation potentials of acoustic phonon in single and double quantum dots under in-plane and out-of-plane magnetic fields, showing that in single quantum dots the relaxation rate is highly sensitive to low in-plane magnetic fields ($<1T$) but converges near a spin-hot-spot region. In a single quantum dot, the spin-hot spot arises from well-understood level crossings between singlet and triplet states. In double quantum dots, a new and unusual spin-hot spot appears as the dots are pulled apart from the origin, with spin-relaxation rates three orders of magnitude lower than conventional single quantum dots. In displaced quantum dots dominated by magnetic confinement, two distinct spin-hot spots appear at different in-plane magnetic field strengths, where spin-relaxation time varies from millisecond to picosecond. When quantum dots are separated by about 60 nm, calculations predict oscillations in spin-hot spots as the in-plane magnetic field changes. These unusual spin-hot spot oscillations occur at low magnetic fields ($<1T$), resulting in spin-relaxation rates about four orders of magnitude lower than those of conventional high-field spin-hot spots ($\approx 4.5T$). The extremely low spin-relaxation rate at the spin-hot spot enables the preparation of qubit superposition states for quantum computing and information processing. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_16947 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | New Source of Spin-hot spot in displaced silicon double quantum dots Prabhakar, Sanjay Mesoscale and Nanoscale Physics Controlling electron spins in double quantum dots allows individual electrons to be trapped and manipulated for next-generation solid-state qubit devices. In this paper, the study analyzes spin relaxation due to deformation potentials of acoustic phonon in single and double quantum dots under in-plane and out-of-plane magnetic fields, showing that in single quantum dots the relaxation rate is highly sensitive to low in-plane magnetic fields ($<1T$) but converges near a spin-hot-spot region. In a single quantum dot, the spin-hot spot arises from well-understood level crossings between singlet and triplet states. In double quantum dots, a new and unusual spin-hot spot appears as the dots are pulled apart from the origin, with spin-relaxation rates three orders of magnitude lower than conventional single quantum dots. In displaced quantum dots dominated by magnetic confinement, two distinct spin-hot spots appear at different in-plane magnetic field strengths, where spin-relaxation time varies from millisecond to picosecond. When quantum dots are separated by about 60 nm, calculations predict oscillations in spin-hot spots as the in-plane magnetic field changes. These unusual spin-hot spot oscillations occur at low magnetic fields ($<1T$), resulting in spin-relaxation rates about four orders of magnitude lower than those of conventional high-field spin-hot spots ($\approx 4.5T$). The extremely low spin-relaxation rate at the spin-hot spot enables the preparation of qubit superposition states for quantum computing and information processing. |
| title | New Source of Spin-hot spot in displaced silicon double quantum dots |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2605.16947 |