Fractional quantum Hall effect and Wigner crystallization in suspended Corbino graphene disk
Competition between liquid and solid states in two dimensional electron system is an intriguing problem in condensed matter physics. At high magnetic fields, the kinetic energy of electrons is suppressed, which favors Wigner crystallization of electrons to a lattice. However, electrons commonly favor an incompressible liquid state, the fractional quantum Hall (FQH) liquid, instead of the Wigner crystal solid phase. We have investigated competing Wigner crystal and FQH liquid phases in atomically thin suspended graphene devices in Corbino geometry, where no topological edge states contribute to the current driven through the sample. Low temperature magneto conductance and transconductance measurements along with $IV$ characteristics all indicate strong charge density dependent modulation of electron transport. Our results indicate FQH phases in a re entrant fashion around crystalline order at filling factors $0.12 0.20$ Building on the unique sample structure, our experiments pave the way for enhanced understanding of the ordered phases of interacting electrons in two dimensions.