Graphene nanoribbons generate a strong third-order nonlinear optical response upon intercalating hexagonal boron nitride

Abstract

An artificial hybrid structure (named as BCNNRs) was designed by inserting wide-gap hexagonal boron nitride (h-BN) nanoribbon in between zero-gap graphene nanoribbon. Third-order nonlinear optical properties of this hybrid structure were calculated by employing the time-dependent density functional theory combined with sum-over-states method. Our calculations reveal that, distinct from individual BN nanoribbons or graphene nanoribbons, the hybrid BCNNRs exhibit a much stronger third-order nonlinear optical response. A giant third-order NLO susceptibility χ⁽³⁾ of 1 × 10⁻⁴ esu is predicted, almost three orders of magnitude larger than that recently experimentally measured for graphene. Furthermore, a maximum third-order non-linear optical response of BCNNRs is obtained by adjusting the size of h-BN nanoribbons. The strong third-order non-linear optical response predicted for BCNNRs originates from the charge redistribution in graphene nanoribbon as h-BN ribbon is inserted. The results reported in this work show that insertion of a wide-gap semiconductor h-BN nanoribbon in zero-gap graphene can give rise to a strong three-order nonlinear optical response, which may guide the future development of structural design and exploration of more advanced nonlinear optical materials.