Spin-valley locked excited states spectroscopy in a one-particle bilayer graphene quantum dot
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arXiv
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| Format: | Preprint |
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2023
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| author | Duprez, Hadrien Cances, Solenn Omahen, Andraz Masseroni, Michele Ruckriegel, Max J. Adam, Christoph Tong, Chuyao Gerber, Jonas Garreis, Rebekka Huang, Wister Gächter, Lisa Taniguchi, Takashi Watanabe, Kenji Ihn, Thomas Ensslin, Klaus |
| author_facet | Duprez, Hadrien Cances, Solenn Omahen, Andraz Masseroni, Michele Ruckriegel, Max J. Adam, Christoph Tong, Chuyao Gerber, Jonas Garreis, Rebekka Huang, Wister Gächter, Lisa Taniguchi, Takashi Watanabe, Kenji Ihn, Thomas Ensslin, Klaus |
| contents | Current semiconductor qubits rely either on the spin or on the charge degree of freedom to encode quantum information. By contrast, in bilayer graphene the valley degree of freedom, stemming from the crystal lattice symmetry, is a robust quantum number that can therefore be harnessed for this purpose. The simplest implementation of a valley qubit would rely on two states with opposite valleys as in the case of a single-carrier bilayer graphene quantum dot immersed in a small perpendicular magnetic field ($B_\perp\lesssim 100$mT). However, the single-carrier quantum dot excited states spectrum has not been resolved to date in the relevant magnetic field range. Here, we fill this gap, by measuring the parallel and perpendicular magnetic field dependence of this spectrum with an unprecedented resolution of $4μ$eV. We use a time-resolved charge detection technique that gives us access to individual tunnel events. Our results come as a direct verification of the predicted spectrum and establish a new upper-bound on inter-valley mixing, equal to our energy resolution. Our charge detection technique opens the door to measuring the relaxation time of a valley qubit in a single-carrier bilayer graphene quantum dot. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2311_12949 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Spin-valley locked excited states spectroscopy in a one-particle bilayer graphene quantum dot Duprez, Hadrien Cances, Solenn Omahen, Andraz Masseroni, Michele Ruckriegel, Max J. Adam, Christoph Tong, Chuyao Gerber, Jonas Garreis, Rebekka Huang, Wister Gächter, Lisa Taniguchi, Takashi Watanabe, Kenji Ihn, Thomas Ensslin, Klaus Mesoscale and Nanoscale Physics Current semiconductor qubits rely either on the spin or on the charge degree of freedom to encode quantum information. By contrast, in bilayer graphene the valley degree of freedom, stemming from the crystal lattice symmetry, is a robust quantum number that can therefore be harnessed for this purpose. The simplest implementation of a valley qubit would rely on two states with opposite valleys as in the case of a single-carrier bilayer graphene quantum dot immersed in a small perpendicular magnetic field ($B_\perp\lesssim 100$mT). However, the single-carrier quantum dot excited states spectrum has not been resolved to date in the relevant magnetic field range. Here, we fill this gap, by measuring the parallel and perpendicular magnetic field dependence of this spectrum with an unprecedented resolution of $4μ$eV. We use a time-resolved charge detection technique that gives us access to individual tunnel events. Our results come as a direct verification of the predicted spectrum and establish a new upper-bound on inter-valley mixing, equal to our energy resolution. Our charge detection technique opens the door to measuring the relaxation time of a valley qubit in a single-carrier bilayer graphene quantum dot. |
| title | Spin-valley locked excited states spectroscopy in a one-particle bilayer graphene quantum dot |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2311.12949 |