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Competing Fractional Quantum Hall and Electron Solid Phases in Graphene
Shaowen Chen1,2, Rebeca Ribeiro-Palau1,3, Kang Yang4,5
1Department of Physics, Columbia University, New York, 10027 New York, USA.
Abstract:
We report experimental observation of the reentrant integer quantum Hall effect in graphene, appearing in the N=2 Landau level. Similar to high-mobility GaAs/AlGaAs heterostructures, the effect is due to a competition between incompressible fractional quantum Hall states, and electron solid phases. The tunability of graphene allows us to measure the B-T phase diagram of the electron solid phase. The hierarchy of reentrant states suggests spin and valley degrees of freedom play a role in determining the ground state energy. We find that the melting temperature scales with magnetic field, and construct a phase diagram of the electron liquid-solid transition.
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