Topological Bloch bands in graphene superlattices.
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.
Walter Burke Institute for Theoretical Physics, California Institute of Technology, CA 91125; Institute for Quantum Information and Matter, and Department of Physics, California Institute of Technology, CA 91125; Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 justin.song.cw@gmail.com levitov@mit.edu.
Justin C W
JC
Song
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139.
Polnop
P
Samutpraphoot
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 justin.song.cw@gmail.com levitov@mit.edu.
Leonid S
LS
Levitov
graphene; topological bands; van der Waals heterostructure