Transport properties of nanostructured graphene

摘要

Despite of its many wonderful properties, pristine graphene has one major drawback: it does not have a band gap, which complicates its applications in electronic devices. Many routes have been suggested to overcome this difficulty, such as cutting graphene into nanoribbons, using chemical methods, or making regular nanoperforations, also known antidot lattices. Theoretically, all these ideas lead to a reasonable band gap, but realizing them in the lab is very difficult because all fabrication steps induce disorder or other nonidealities, with potentially disasterous consequences for the intended device operation. In this talk I elaborate these ideas and review the state-of-the-art both from the theoretical and the experimental points of view. I also introduce two new ideas: (1) triangular antidots, and (2) nanobubbles formed in graphene. Both of these nanostructuring methods are predicted to yield novel transport signatures, which could form the basis of new types of devices. Our simulations show that it may be possible to generate very high quality spin- and/or valley polarized currents with these structures — something that has not yet been achieved in the lab. Importantly, our simulations involve millions of atoms which is necessary in order to address structures feasible in the lab.