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

Krishna Kumar, R. Krishna; Chen, X.; Auton, G.H.; Mishchenko, A.; Bandurin, Denis A.; Morozov, S.V.; Cao, Y.; Khestanova, E.; Ben Shalom, M.; Kretinin, A.V.; Novoselov, K.S.; Eaves, Laurence; Grigorieva, Irina V.; Ponomarenko, L.A.; Fal�ko, V.I.; Geim, A.K.

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.

Citation

Krishna Kumar, R. K., Chen, X., Auton, G., Mishchenko, A., Bandurin, D. A., Morozov, S., Cao, Y., Khestanova, E., Ben Shalom, M., Kretinin, A., Novoselov, K., Eaves, L., Grigorieva, I. V., Ponomarenko, L., Fal’ko, V., & Geim, A. (2017). High-temperature quantum oscillations caused by recurring Bloch states in graphene superlattices. Science, 357(6347), 181-184. https://doi.org/10.1126/science.aal3357

• Journal Article Type: Article
• Acceptance Date: Jun 29, 2017
• Publication Date: Jul 14, 2017
• Deposit Date: Jul 17, 2017
• Publicly Available Date: Jul 17, 2017
• Journal: Science
• Print ISSN: 0036-8075
• Electronic ISSN: 1095-9203
• Publisher: American Association for the Advancement of Science
• Peer Reviewed: Peer Reviewed
• Volume: 357
• Issue: 6347
• Pages: 181-184
• DOI: https://doi.org/10.1126/science.aal3357
• Public URL: https://nottingham-repository.worktribe.com/output/872730
• Publisher URL: http://science.sciencemag.org/content/357/6347/181
• 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
• Contract Date: Jul 17, 2017