High-temperature quantum oscillations caused by recurring Bloch states in graphene superlattices

Krishna Kumar, R. and Chen, X. and Auton, G.H. and Mishchenko, A. and Bandurin, Denis A. and Morozov, S.V. and Cao, Y. and Khestanova, E. and Ben Shalom, M. and Kretinin, A.V. and Novoselov, K.S. and Eaves, Laurence and Grigorieva, Irina V. and Ponomarenko, L.A. and Fal’ko, V.I. and Geim, A.K. (2017) High-temperature quantum oscillations caused by recurring Bloch states in graphene superlattices. Science, 357 (6347). pp. 181-184. ISSN 1095-9203

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Abstract

Cyclotron motion of charge carriers in metals and semiconductors leads to Landau quantization and magneto-oscillatory behavior in their properties. Cryogenic temperatures are usually required to observe these oscillations. We show that graphene superlattices support a different type of quantum oscillations that do not rely on Landau quantization. The oscillations are extremely robust and persist well above room temperature in magnetic fields of only a few T. We attribute this phenomenon to repetitive changes in the electronic structure of superlattices such that charge carriers experience effectively no magnetic field at simple fractions of the flux quantum per superlattice unit cell. Our work points at unexplored physics in Hofstadter butterfly systems at high temperatures.

Item Type: Article
Additional Information: This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science on Vol. 357, 14 July 2017, DOI: 10.1126/science.aal3357
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: 10.1126/science.aal3357
Depositing User: Eprints, Support
Date Deposited: 17 Jul 2017 09:01
Last Modified: 12 Oct 2017 23:05
URI: http://eprints.nottingham.ac.uk/id/eprint/44216

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