Phonon-limited valley life times in single-particle bilayer graphene quantum dots
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arXiv
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| Autori principali: | , , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866918091919720448 |
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| author | Banszerus, Luca Hecker, Katrin Wang, Lin Möller, Samuel Watanabe, Kenji Taniguchi, Takashi Burkard, Guido Volk, Christian Stampfer, Christoph |
| author_facet | Banszerus, Luca Hecker, Katrin Wang, Lin Möller, Samuel Watanabe, Kenji Taniguchi, Takashi Burkard, Guido Volk, Christian Stampfer, Christoph |
| contents | The valley degree of freedom in 2D semiconductors, such as gapped bilayer graphene (BLG) and transition metal dichalcogenides, is a promising carrier of quantum information in the emerging field of valleytronics. While valley dynamics have been extensively studied for moderate band gap 2D~semiconductors using optical spectroscopy techniques, very little is known about valley lifetimes in narrow band gap BLG, which is difficult to study using optical techniques. Here, we report single-particle valley relaxation times ($T_1$) exceeding several microseconds in electrostatically defined BLG quantum dots (QDs) using a pulse-gating technique. The observed dependence of $T_1$ on perpendicular magnetic field can be understood qualitatively and quantitatively by a model in which $T_1$ is limited by electron-phonon coupling. We identify the coupling to acoustic phonons via the bond length change and via the deformation potential as the limiting mechanisms. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_16691 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Phonon-limited valley life times in single-particle bilayer graphene quantum dots Banszerus, Luca Hecker, Katrin Wang, Lin Möller, Samuel Watanabe, Kenji Taniguchi, Takashi Burkard, Guido Volk, Christian Stampfer, Christoph Mesoscale and Nanoscale Physics Quantum Physics The valley degree of freedom in 2D semiconductors, such as gapped bilayer graphene (BLG) and transition metal dichalcogenides, is a promising carrier of quantum information in the emerging field of valleytronics. While valley dynamics have been extensively studied for moderate band gap 2D~semiconductors using optical spectroscopy techniques, very little is known about valley lifetimes in narrow band gap BLG, which is difficult to study using optical techniques. Here, we report single-particle valley relaxation times ($T_1$) exceeding several microseconds in electrostatically defined BLG quantum dots (QDs) using a pulse-gating technique. The observed dependence of $T_1$ on perpendicular magnetic field can be understood qualitatively and quantitatively by a model in which $T_1$ is limited by electron-phonon coupling. We identify the coupling to acoustic phonons via the bond length change and via the deformation potential as the limiting mechanisms. |
| title | Phonon-limited valley life times in single-particle bilayer graphene quantum dots |
| topic | Mesoscale and Nanoscale Physics Quantum Physics |
| url | https://arxiv.org/abs/2402.16691 |