Thermodynamic properties of pure and doped (B, N) graphene

Abstract

Ab-initio density functional perturbation theory (DFPT) has been employed to study thermodynamical properties of pure and doped graphene sheet and the results have been compared with available theoretical and experimental data. The concentration of B and N has been varied upto 50% of the carbon atoms in graphene. Phonon frequencies are essential ingredients entering into such a calculation, which have been computed by using the dynamical matrix provided by VASP software in combination with phonopy code in the harmonic approximation. This easily provides us the Helmholtz free energy and leads us to numerical estimates of various thermodynamical properties. The results for specific heat are in good agreement with various theoretical and experimental studies obtained earlier for pure graphene. Interesting new results have been reported for B and N substituted structure. It has been observed that specific heat decreases with the increase in concentration of doping while the entropy increases. Further, large doping concentrations result in unstable sheets resulting in imaginary frequencies in the transverse directions. The instability needs to be compensated by external strains and that has been assumed while carrying out Brilluoin summations. These results will be useful for calculation of thermal conductivity of doped graphene and thus feasibility of using these for device applications. Our preliminary results for thermal expansion have indicated negative thermal expansion behavior of pure graphene at low temperatures which needs investigation on doped graphene as well.

20 pages, 41 references, 12 figures in RSC Adv 2016

References in corpus (7)

• Electric Field Effect in Atomically Thin Carbon Films
• Thermal properties of graphene: Fundamentals and applications
• Negative Thermal Expansion Coefficient of Graphene Measured by Raman Spectroscopy
• The phonon dispersion of graphite by inelastic x-ray scattering
• A Review on Flexural Mode of Graphene: Lattice Dynamics, Thermal Conduction, Thermal Expansion, Elasticity, and Nanomechanical Resonance
• Hole doped Dirac states in silicene by biaxial tensile strain
• Plane polarized-longitudinal Phonons in realistic low dimensional systems

Cited by in corpus (9)

• Effects of bonded and non-bonded B/N codoping of graphene on its stability,\break interaction energy, electronic structure, and power factor
• High-Temperature Conventional Superconductivity in the Boron-Carbon system: Material Trends
• MoB2:a new multifunctional transition metal diboride monolayer
• Phonons and Thermal Conducting Properties of Borocarbonitride (BCN) Nanosheets
• Lattice thermal conductivity of pristine and doped (B,N) Graphene
• Thermal properties of graphene from path-integral simulations
• Thermodynamic properties of graphene bilayers
• Thermal properties of graphene under tensile stress
• Nuclear quantum effects in graphene bilayers