SIMULATION OF TWISTED BILAYER GRAPHENE STRUCTURE AND INVESTIGATION OF CONCENTRATION DEPENDENCE OF HYDROGEN AND FLUORINE ADSORBED ON ITS SURFACE ON THE ROTATION ANGLE

A simulation method is used to study the structure of pristine and defective twisted graphene with a large number of atoms. An algorithm is developed and implemented for determination of AA-, AB-, and BA-stacked superstructures on the twisted graphene surface. Dependence of the fluorine and hydrogen concentration on the interlayer twist angle is explored for four different adsorption sites. The maximum concentration of adsorbate atoms with full coverage of the studied adsorption sites and the corresponding twist angles are found. The Cowley short-range order parameters are calculated. The analysis of these parameters for two configurations reveals that short-range and long-range ordering of various types is possible in fluorinated and hydrogenated twisted graphene at angles ranging from 2 degrees to 58 degrees. The results can be useful in studying functionalization of materials with a hexagonal structure and the same adsorption sites.