Landau Level Crossings in Dual-Gated Bilayer Graphene at Large Displacement Fields

Previous work shows that Landau levels in bilayer graphene with the same orbital index $N$ but different spin and valley degrees of freedom can form superpositions at a finite electric field[1-2]. Using the technique of one dimensional edge contacts[3] we fabricate dual-gated boron-nitride-encapsulated bilayer graphene device with a graphite local gate, which enables us to apply large electric fields and observe Landau level crossings between levels with neighboring orbital indices. We will discuss our latest results. [1] R. T. Weitz et al., Science 330, 812-816 (2010). [2] K. Lee et al., Science 345, 58-61 (2014). [3] L. Wang et al., Science 342, 614-617 (2013)