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| Main Authors: | , , , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2504.08429 |
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| _version_ | 1866916685680738304 |
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| author | Brosda, Nico F. Badura, Phil J. Bölükbaşı, İsmail Engin, İbrahim Lindner, Patrick Valentin, Sascha R. Wieck, Andreas D. Sothmann, Björn Ludwig, Arne |
| author_facet | Brosda, Nico F. Badura, Phil J. Bölükbaşı, İsmail Engin, İbrahim Lindner, Patrick Valentin, Sascha R. Wieck, Andreas D. Sothmann, Björn Ludwig, Arne |
| contents | Inhomogeneous ensembles of quantum dots (QDs) coupled to a charge reservoir are widely studied by using, e.g., electrical methods like capacitance-voltage spectroscopy. We present experimental measurements of the QD capacitance as a function of varying parameters such as ac frequency and bath temperature. The experiment reveals distinct shifts in the position of the capacitance peaks. While temperature-induced shifts have been explained by previous models, the observation of frequency-dependent shifts has not been explained so far. Given that existing models fall short in explaining these phenomena, we propose a refined theoretical model based on a master equation approach which incorporates energy-dependent tunneling effects. This approach successfully reproduces the experimental data. We highlight the critical role of energy-dependent tunneling in two distinct regimes: at low temperatures, ensemble effects arising from energy-level dispersion in differently sized QDs dominate the spectral response; at high temperatures and frequencies, we observe a peak shift of a different nature, which is best described by optimizing the conjoint probability of successive in- and out-tunneling events. Our findings contribute to a deeper understanding of tunnel processes and the physical properties of QD ensembles coupled to a common reservoir, with implications for their development in applications such as single-photon sources and spin qubits. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_08429 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Towards quantitative understanding of quantum dot ensemble capacitance-voltage spectroscopy Brosda, Nico F. Badura, Phil J. Bölükbaşı, İsmail Engin, İbrahim Lindner, Patrick Valentin, Sascha R. Wieck, Andreas D. Sothmann, Björn Ludwig, Arne Mesoscale and Nanoscale Physics Other Condensed Matter Statistical Mechanics Inhomogeneous ensembles of quantum dots (QDs) coupled to a charge reservoir are widely studied by using, e.g., electrical methods like capacitance-voltage spectroscopy. We present experimental measurements of the QD capacitance as a function of varying parameters such as ac frequency and bath temperature. The experiment reveals distinct shifts in the position of the capacitance peaks. While temperature-induced shifts have been explained by previous models, the observation of frequency-dependent shifts has not been explained so far. Given that existing models fall short in explaining these phenomena, we propose a refined theoretical model based on a master equation approach which incorporates energy-dependent tunneling effects. This approach successfully reproduces the experimental data. We highlight the critical role of energy-dependent tunneling in two distinct regimes: at low temperatures, ensemble effects arising from energy-level dispersion in differently sized QDs dominate the spectral response; at high temperatures and frequencies, we observe a peak shift of a different nature, which is best described by optimizing the conjoint probability of successive in- and out-tunneling events. Our findings contribute to a deeper understanding of tunnel processes and the physical properties of QD ensembles coupled to a common reservoir, with implications for their development in applications such as single-photon sources and spin qubits. |
| title | Towards quantitative understanding of quantum dot ensemble capacitance-voltage spectroscopy |
| topic | Mesoscale and Nanoscale Physics Other Condensed Matter Statistical Mechanics |
| url | https://arxiv.org/abs/2504.08429 |