  A conversion of AA- to AB-stacking bilayer graphene (BLG) due to interlayer
interaction is demonstrated. Two types of interlayer interactions, an
attractive and a repulsive, between the Boron and Nitrogen dopant atoms in BLG
are found. In the presence of the attractive interaction, an AA-stacking of
BN-codoped BLG is formed with a less stable structure leading to weak
mechanical properties of the system. Low values of the Young modulus, the
ultimate strength and stress, and the fracture strength are observed comparing
to a pure BLG. In addition, the attractive interaction induces a small bandgap
that deteriorates the thermal and optical properties of the system. In
contrast, in the presence of a repulsive interaction between the B and N atoms,
the AA-stacking is converted to a AB-stacking with a more stable structure.
Improved mechanical properties such as higher Young modulus, the ultimate
strength and stress, fracture strength are obtained comparing to the AA-stacked
BN-codoped BLG. Furthermore, a larger bandgap of the AB-stacked bilayer
enhances the thermal and the optical characteristics of the system.
