Stacking symmetry governed second harmonic generation in graphene trilayers.

ABSTRACT: Crystal symmetry plays a central role in governing a wide range of fundamental physical phenomena. One example is nonlinear optical second harmonic generation (SHG), which requires inversion symmetry breaking. We report a unique stacking-induced SHG in graphene trilayers, whose individual monolayer sheet is centrosymmetric. Depending on layer stacking sequence, we observe a strong optical SHG in a Bernal ABA-stacked non-centrosymmetric trilayer, while it vanishes in a rhombohedral ABC-stacked one, which preserves inversion symmetry. This highly contrasting SHG due to the distinct stacking symmetry enables us to map out the ABA and ABC crystal domains in an otherwise homogeneous graphene trilayer. The extracted second-order nonlinear susceptibility of the ABA trilayer is surprisingly large,

SUBMITTER: Shan Y 

PROVIDER: S-EPMC6003727 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature