Quantum transport in high-quality Bilayer Graphene pnp Junctions

Using high-quality bilayer grapheme pnp junctions with suspended top gates, we perform transport measurements. At a magnetic field B=0, by an applied perpendicular electric field, band gap opens at 260mK. Within the band gap, we demonstrate the conductance decreases exponentially by 3 orders of magnitude with increasing electric field and this can be explained by variable range hopping with a gate-tunable density of states, effective mass, and localization length.