Topological Bloch bands in graphene superlattices

• Main Authors: Song, Justin C. W. (Contributor), Samutpraphoot, Polnop (Contributor), Levitov, Leonid (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor)
• Format: Article
• Language: English
• Published: National Academy of Sciences (U.S.), 2016-04-04T16:39:58Z.
• Subjects: Article
• Online Access: Get fulltext

We outline a designer approach to endow widely available plain materials with topological properties by stacking them atop other nontopological materials. The approach is illustrated with a model system comprising graphene stacked atop hexagonal boron nitride. In this case, the Berry curvature of the electron Bloch bands is highly sensitive to the stacking configuration. As a result, electron topology can be controlled by crystal axes alignment, granting a practical route to designer topological materials. Berry curvature manifests itself in transport via the valley Hall effect and long-range chargeless valley currents. The nonlocal electrical response mediated by such currents provides diagnostics for band topology.
National Science Foundation (U.S.). Science and Technology Center for Integrated Quantum Materials
National Science Foundation (U.S.) (Grant DMR-1231319)
Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (Contract W911NF-13-D-0001)