Density dependence of the excitation gaps in an undoped Si/SiGe double-quantum-well heterostructure
| Autor: | Chen, D., Cai, S., Hsu, N. -W., Huang, S. -H., Chuang, Y., Nielsen, E., Li, J. -Y., Liu, C. W., Lu, T. M., Laroche, D. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Appl. Phys. Lett. 119, 223103 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1063/5.0068538 |
| Popis: | We report low-temperature magneto-transport measurements of an undoped Si/SiGe asymmetric double quantum well heterostructure. The density in both layers is tuned independently utilizing a top and a bottom gate, allowing the investigation of quantum wells at both imbalanced and matched densities. Integer quantum Hall states at total filling factor $\nu_{\text{T}} = 1$ and $\nu_{\text{T}} = 2$ are observed in both density regimes, and the evolution of their excitation gaps is reported as a function of density. The $\nu_{\text{T}} = 1$ gap evolution departs from the behavior generally observed for valley splitting in the single layer regime. Furthermore, by comparing the $\nu_{\text{T}} = 2$ gap to the single particle tunneling energy, $\Delta_{\text{SAS}}$, obtained from Schr\"{o}dinger-Poisson (SP) simulations, evidence for the onset of spontaneous inter-layer coherence (SIC) is observed for a relative filling fraction imbalance smaller than ${\sim}50\%$ Comment: 6 pages, 3 figures, accepted in APL |
| Databáze: | arXiv |
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