Thermal Conductivity of Pure and Doped Graphene

In this work we have studied the thermal conductivity of both pure graphene and boron-doped graphene structure. The calculations have been performed using ab-initio density functional perturbation theory, implemented in VASP software, to study structural properties and calculated the interatomic forces/force constants of pristine/doped graphene. Thermal conductivities are calculated by solving linearized Boltzmann transport equations (LBTE) using single mode relaxation time approximation (RTA). The phonon density of states and thermal conductivity were calculated using phonopy and phono3py. A graphene sheet of 32 atoms was considered for calculating second order force constants while an 8 atom sheet was used to calculate third order force constants. A smaller sheet was used for third order force constant calculation as it requires high computation. Doping concentrations of 12.5% and 25% B dopants were used in this work since higher concentration of dopants lead to unstable structures.

Using this approach, we have obtained thermal expansion results for pure graphene which match well earlier calculations using similar approach The results have suggested that the thermal properties could be highly tuneable and have interesting application prospects