Floating up of the zero-energy Landau level in monolayer epitaxial graphene
Autor: | Huang, Lung-I, Yang, Yanfei, Elmquist, Randolph E., Lo, Shun-Tsung, Liu, Fan-Hung, Liang, Chi-Te |
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Rok vydání: | 2016 |
Předmět: | |
Druh dokumentu: | Working Paper |
Popis: | We report on magneto-transport measurements on low-density, large-area monolayer epitaxial graphene devices grown on SiC. We show that the zero-energy Landau level (LL) in monolayer graphene, which is predicted to be magnetic field ($B$)-independent, can float up above the Fermi energy at low $B$. This is supported by the temperature ($T$)-driven flow diagram approximated by the semi-circle law as well as the $T$-independent point in the Hall conductivity $\sigma_{xy}$ near $e^2/h$. Our experimental data are in sharp contrast to conventional understanding of the zeroth LL and metallic-like behavior in pristine graphene prepared by mechanical exfoliation at low $T$. This surprising result can be ascribed to substrate-induced sublattice symmetry breaking which splits the degeneracy of the zeroth Landau level. Our finding provides a unified picture regarding the metallic behavior in pristine graphene prepared by mechanical exfoliation, and the insulating behavior and the insulator-quantum Hall transition in monolayer epitaxial graphene. Comment: 4 figures with supplementary Information |
Databáze: | arXiv |
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