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Title: Final Report on Investigation of the Electron Interactions in Graphene

In graphene, combined with the real spin degree of freedom, which exhibits SU(2) symmetry, the total internal degrees of freedom of graphene carriers is thus described by a larger SU(4) symmetry, which produces a richer space for potential phenomena of emergent correlated electron phenomena. The major part of this proposal is exploring this unique multicomponent correlated system in the quantum limit. In the current period of DOE BES support we have made several key advances that will serve as a foundation for the new studies in this proposal. Employing the high-mobility encapsulated graphene heterostructures developed during the current phase of research, we have investigated spin and valley quantum Hall ferromagnetism in graphene and discovered a spin phase transition leading to a quantum spin Hall analogue. We have also observed the fractal quantum Hall effect arising from the Hofstadter’s butterfly energy spectrum. In addition, we have discovered multiband transport phenomena in bilayer graphene at high carrier densities.
Authors:
 [1]
  1. Columbia University
Publication Date:
OSTI Identifier:
1170221
Report Number(s):
DOE-COLUMBIA--FG02-05ER46215
DOE Contract Number:
FG02-05ER46215
Resource Type:
Technical Report
Research Org:
Columbia Univ., New York, NY (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE Graphene; quantum transport; electron Interactions