Vibrations and Buckling of Uni-Axially Strained Graphene and BN-Monolayer: A First-Principles Study - Graphene and Its Fascinating Attributes - page 84

BN-monolayer. The compressive strain along -directions softens the

M point optical modes with out-of plane displacements for graphene. Inter-
esting features arise in the acoustic flexural modes. The acoustic flexural
modes for q along

Z -or A

A -direction hardly change with the application of com-

pressive strain along Z -direction for graphene, but soften if the compressive

strain along -direction. On the other hand, the acoustic and optical flex-

ural modes of BN-monolayer soften with compressive strain applied along
either of

A

Z -and A -directions.

Fig. 5. (Color online) (a) The parameter α at different compressive strain, (b) Flexural
modes of graphene and BN-monolayer at different compressive strain.

Fig. 6. (Color online) Eigen displacements of C atoms of graphene with compressive
strain of -1.5 % along -direction (a) 0 cm − 1 (b) 479 cm − 1 (c) 636 cm − 1 (d) 905 cm − 1 ,

and those of B and N atom of BN-monolayer with compressive strain of -1.5 % along
Z -direction (e) 0 cm − 1 (f) 311 cm − 1 (g) 629 cm − 1 (h) 823 cm − 1 .

Z