Vibrations and Buckling of Uni-Axially Strained Graphene and BN-Monolayer: A First-Principles Study - Graphene and Its Fascinating Attributes - page 88

stain, (irrespective of the -direction) where the insulating nature of

BN-monolayer changes to metallic, the bond lengths vary for strain applied
in

Z -or A

-direction. The dis-similarity
in bond length along with the electronegative difference of B and N atoms,
drives the electron cloud more towards the N atom, which is reflected in
the contour plot in Fig. 8. With the applied strain the shape of the elec-
tron cloud also distorts as revealed from the Fig. 8(b) (compressive strain
is applied along Z-direction) and Fig. 8(c) (compressive strain is applied
along A direction), those differ from Fig. 8(a) where the electron cloud is
distributed isotropically.

Z -direction and that of strain applied in A

4. Conclusion

In conclusion, we have presented a comparative study of flexural modes of
graphene and BN-monolayer. The critical uniaxial compressive strain along
Z

-direction of graphene is -1.93 % while it is -1.77 % for BN-monolayer at
which buckling occurs. Compared to BN-monolayer, graphene exhibit a
stronger anisotropy in changes in the inter-atomic forces due to uni-axial
strain. At around 20 % of compressive strain insulating BN-monolayer
becomes metallic. We suggest that strained BN-monolayer can be used as
a tunable bandgap material for various applications.

Acknowledgment

We acknowledge funding from DRDO.

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