  Competition between liquid and solid states in two-dimensional electron
system is an intriguing problem in condensed matter physics. We have
investigated competing Wigner crystal and fractional quantum Hall ( FQH )
liquid phases in atomically thin suspended graphene devices in Corbino
geometry. Low temperature magnetoconductance and transconductance measurements
along with $IV$ characteristics all indicate strong charge density dependent
modulation of electron transport. Our results show unconventional FQH phases
which do not fit the standard Jain's series for conventional FQH states,
instead they appear to originate from residual interactions of composite
fermions in partially filled higher Landau levels. And at very low charge
density with filling factors $\nu \lesssim$ 1/5, electrons crystallize into an
ordered Wigner solid which eventually transforms into an incompressible Hall
liquid at filling factors around $\nu \leq$ 1/7. Building on the unique sample
structure, our experiments pave the way for enhanced understanding of the
ordered phases of interacting electrons.
