Electron interactions and gap opening in graphene superlattices.
We develop a theory of interaction effects in graphene superlattices, where tunable superlattice periodicity can be used as a knob to control the gap at the Dirac point. Applied to graphene on hexa-boron-nitride (G/h-BN), our theory predicts substantial many-body enhancement of this gap. Tunable by the moiré superlattice periodicity, a few orders of magnitude enhancement is reachable under optimal conditions. The Dirac point gap enhancement can be much larger than that of the minigaps opened by Bragg scattering at principal superlattice harmonics. This naturally explains the conundrum of large Dirac point gaps recently observed in G/h-BN heterostructures and their tunability by the G/h-BN twist angle.
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Justin C W
JC
Song
School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, United Kingdom.
Andrey V
AV
Shytov
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Leonid S
LS
Levitov