Seminarium "Teoria i Modelowanie Nanostruktur"

We report the studies of BxC1-x, NxC1-x, and BxNyC1-x-y layered graphene based alloy structures containing typical for graphene internal defects, such as single and multiple vacancies, 5-7 Stone-Wales defects, and grain boundaries. We extent our studies also to the systems with reduced periodicity just considering the alloyed nano-ribbons and platelets. Through the studies of energetics of the system, we determine first the thermodynamic equilibrium morphology of the studied systems and then we analyze short-range and long-range ordering, as quantified by the Warren-Cowley short-range order parameter. This comprehensive analysis covers relevant range temperatures and is based on Monte Carlo (MC) calculations within the NVT ensemble employing Metropolis algorithm and Valence Force Field (VFF) approach to calculate the total energies of the of the system. We perform also density functional theory based calculations (employing the SIESTA and sometimes VASP code) to test the predictions of VFF potential. We have also implemented into the computational algorithm the conjugate-gradient method to determine the equilibrium geometry.