文章基本信息

标题：Fabry–Pérot resonances and a crossover to the quantum Hall regime in ballistic graphene quantum point contacts
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作者：Nurul Fariha Ahmad ; Katsuyoshi Komatsu ; Takuya Iwasaki 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2019
卷号：9
期号：1
页码：1-7
DOI：10.1038/s41598-019-39909-5
出版社：Springer Nature
摘要：We report on the observation of quantum transport and interference in a graphene device that is attached with a pair of split gates to form an electrostatically-defined quantum point contact (QPC). In the low magnetic field regime, the resistance exhibited Fabry-Pérot (FP) resonances due to np'n(pn'p) cavities formed by the top gate. In the quantum Hall (QH) regime with a high magnetic field, the edge states governed the phenomena, presenting a unique condition where the edge channels of electrons and holes along a p-n junction acted as a solid-state analogue of a monochromatic light beam. We observed a crossover from the FP to QH regimes in ballistic graphene QPC under a magnetic field with varying temperatures. In particular, the collapse of the QH effect was elucidated as the magnetic field was decreased. Our high-mobility graphene device enabled observation of such quantum coherence effects up to several tens of kelvins. The presented device could serve as one of the key elements in future electronic quantum optic devices.