Vibrational Properties Of Substitutional Hexagonal Boron Nitride Sheets

We have theoretically studied the pristine and one and more than one carbon atoms substituted hexagonal boron nitride (h-BN) sheet using density-functional theory. The optimal geometries, work function and vibrational properties are obtained. Phonon dispersion curves show that the single carbon atom doped h-BN sheets are dynamically stable, whereas four carbon atoms doped h-BN are not. There are significant changes in the behavior of phonon modes after substitution. Out of plane acoustic mode turns linear indicating for higher group velocity and more contribution to the thermal conductivity and thermal conductance. Our calculations show that the work function depends on the bandgap.