Download or read book Transport Properties of Few-layer Graphene on Boron Nitride written by Bin Cheng and published by . This book was released on 2015 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: The electronic transport properties of graphene on hexagonal boron nitride (hBN) have been studied intensively in the past few years, and rich phenomena such as the fractal Hofstadter's butterfly energy spectrum and Landau level crossing have been observed. This thesis reports our transport measurements on few-layer graphene on hBN. First, I present our bilayer graphene devices in which the bilayers are aligned to the hBN lattice, creating a superlattice potential due to the lattice and angular mismatch. The energy band structure is strongly altered at the edges of the reduced Brillouin zone, and can be tuned by a perpendicular electric field. As a strong magnetic field turned on, the Hofstadter's butterfly spectrum emerges which can also be tuned by electric field. The valley symmetry breaks due to the asymmetric coupling to the aligned hBN, while the valley symmetry is dramatically restored at a critical electric field, with the electron and hole doped regimes showing the opposite critical electric field. I then show our data from twisted trilayer graphene samples with a large twist angle. The Landau levels of massive fermions from the bilayer graphene cross with those of the massless fermions from the monolayer graphene, producing a unique Landau level crossing spectrum.