2017/05/31 by Roshan Krishna Kumar, R. Krishna Kumar, X. Chen +24 · 1 voice · 3 citations
Materials Science · Physics and Astronomy · #Graphene research and applications #Quantum and electron transport phenomena #Topological Materials and Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1126/science.aal3357
published as Science 357, 181-184 (2017)
arxiv created 2017/05/31 · openalex created_date 2017/06/05 · openalex publication_date 2017/07/14 · arxiv updated 2017/07/18 · openalex updated_date 2026/08/04
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.