| AVS 60th International Symposium and Exhibition | |
| Graphene and Other 2D Materials Focus Topic | Tuesday Sessions |
| Session GR+AS+NS+SP+SS-TuA |
| Session: | Characterization including Microscopy and Spectroscopy of 2D Materials |
| Presenter: | B.J. LeRoy, University of Arizona |
| Correspondent: | Click to Email |
Scanning probe microscopy is a powerful tool to probe low-dimensional systems. The local information provided by scanning probe microscopy is invaluable for studying effects such as interactions and scattering. Using this approach, we have probed the local electronic properties of graphene. The honeycomb lattice in graphene creates a unique linear dispersion relation and the charge carriers behave as massless fermions near the Dirac point. We have studied the effect of charged impurities and the underlying substrate on the local density of states. We find that long‑range scattering from charged impurities locally shifts the charge neutrality point leading to electron and hole doped regions. By using boron nitride as a substrate, we observe an improvement in the electronic properties of the graphene as well as a moire pattern due to the misalignment of the graphene and boron nitride lattices [1]. We find that the periodic potential due to the boron nitride substrate creates a set of 6 new superlattice Dirac points in graphene [2]. The ultraflat and clean nature of graphene on boron nitride devices allows for the observation of scattering from buried step edges, which is used to map the dispersion relation [3]. More complicated graphene heterostructures can be created by adding additional layers or other two-dimensional materials. Our latest results with trilayer graphene and rotated bilayers will also be discussed.
[1] J. Xue et al., Nature Materials 10, 282 (2011).
[2] M. Yankowitz et al., Nature Physics 8, 382 (2012).
[3] J. Xue et al., Phys. Rev. Lett. 108, 016801 (2012).