Fractional topological phases, triplet superconductivity and spontaneous time reversal symmetry breaking in strained graphene

ORAL

Abstract

Despite wide interests to realize fractional time-reversal symmetric phases, an experimentally realizable system with these exotic topological orders is still lacking. Recent experiment has confirmed that strain can be used to control the electronic states of graphene and create flat pseudo-Landau levels in the absence of external magnetic field. In this talk, I show that graphene under strain is a natural playground for the observation of exotic phases such as fractional valley Hall insulator as well as flat band superconductivity. For neutral graphene, we find a competition between the Ising valley ferromagnet and the spin ferromagnet ruled by the value of short range Hubbard and long range Coulomb interactions. At fractional filling with different intervalley and intravalley interactions, a spin triplet superconductor, a valley-polarized Laughlin state or a time-reversal symmetric fractional valley-Hall state could be realized.

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Authors

  • Pouyan Ghaemi

    Departmant of Physics, University of Illinois, Urbana, IL 61801, USA, University of Illinois at Urbana-Champaign

  • Jerome Cayssol

    LOMA, University Bordeaux-1, France, Max-Planck-Institut f\"ur Physik komplexer Systeme, N\"othnitzer Str. 38, 01187 Dresden, Germany, LOMA (UMR-5798), CNRS and University Bordeaux, F-33045 Talence, France

  • Donna Sheng

    Department of Physics and Astronomy, California State University Northridge, Northridge, California, 91325, USA, Department of Physics and Astronomy, California State University, Department of Physics and Astronomy, California State University, Northridge, California 91330, USA

  • Ashvin Vishwanath

    UC Berkeley, University of California, Berkeley, Department of Physics, University of California, Berkeley, CA 94720, USA