Huber, Robin and Steffen, Max-Niklas and Drienovsky, Martin and Sandner, Andreas and Watanabe, Kenji and Taniguchi, Takashi and Pfannkuche, Daniela and Weiss, Dieter and Eroms, Jonathan (2022) Band conductivity oscillations in a gate-tunable graphene superlattice. NATURE COMMUNICATIONS, 13 (1): 2856. ISSN 2041-1723
Full text not available from this repository. (Request a copy)Abstract
Electrons exposed to a two-dimensional (2D) periodic potential and a uniform, perpendicular magnetic field exhibit a fractal, self-similar energy spectrum known as the Hofstadter butterfly. Recently, related high-temperature quantum oscillations (Brown-Zak oscillations) were discovered in graphene moire systems, whose origin lies in the repetitive occurrence of extended minibands/magnetic Bloch states at rational fractions of magnetic flux per unit cell giving rise to an increase in band conductivity. In this work, we report on the experimental observation of band conductivity oscillations in an electrostatically defined and gate-tunable graphene superlattice, which are governed both by the internal structure of the Hofstadter butterfly (Brown-Zak oscillations) and by a commensurability relation between the cyclotron radius of electrons and the superlattice period (Weiss oscillations). We obtain a complete, unified description of band conductivity oscillations in two-dimensional superlattices, yielding a detailed match between theory and experiment. Experiments in a tunable graphene superlattice show that the unusual 1/B periodic resistance oscillations at high temperatures in the energy spectrum of electrons in a 2D periodic potential, known as the Hofstadter butterfly, coexist with oscillations due to commensurability between the electron cyclotron radius and the superlattice's period.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | MAGNETORESISTANCE OSCILLATIONS; ELECTRONIC-PROPERTIES; BLOCH ELECTRONS; DIRAC FERMIONS |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Chair Professor Weiss > Group Dieter Weiss Physics > Institute of Experimental and Applied Physics > Chair Professor Weiss > Group Jonathan Eroms |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 15 Feb 2024 06:00 |
| Last Modified: | 15 Feb 2024 06:00 |
| URI: | https://pred.uni-regensburg.de/id/eprint/57544 |
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