Firstprinciples determination of the structural, vibrational and thermodynamic properties of diamond, graphite, and derivatives
Abstract
The structural, dynamical, and thermodynamic properties of diamond, graphite and layered derivatives (graphene, rhombohedral graphite) are computed using a combination of densityfunctional theory totalenergy calculations and densityfunctional perturbation theory lattice dynamics in the generalized gradient approximation. Overall, very good agreement is found for the structural properties and phonon dispersions, with the exception of the c/a ratio in graphite and the associated elastic constants and phonon dispersions. Both the C_{33} elastic constant and the Γ to A phonon dispersions are brought to close agreement with available data once the experimental c/a is chosen for the calculations. The vibrational free energy and the thermal expansion, the temperature dependence of the elastic moduli and the specific heat are calculated using the quasiharmonic approximation. Graphite shows a distinctive inplane negative thermalexpansion coefficient that reaches its lowest value around room temperature, in very good agreement with experiments. Thermal contraction in graphene is found to be three times as large; in both cases, bending acoustic modes are shown to be responsible for the contraction, in a direct manifestation of the membrane effect predicted by Lifshitz over 50years ago. Stacking directly affects the bending modes, explaining the large numerical difference between the thermalcontraction coefficients in graphite and graphene, notwithstanding their common physical origin.
 Publication:

Physical Review B
 Pub Date:
 May 2005
 DOI:
 10.1103/PhysRevB.71.205214
 arXiv:
 arXiv:condmat/0412643
 Bibcode:
 2005PhRvB..71t5214M
 Keywords:

 71.15.Mb;
 81.05.Uw;
 65.40.b;
 63.20.Dj;
 Density functional theory local density approximation gradient and other corrections;
 Carbon diamond graphite;
 Thermal properties of crystalline solids;
 Phonon states and bands normal modes and phonon dispersion;
 Condensed Matter  Materials Science
 EPrint:
 Revtex, 17 pages, 26 postscript figures, submitted to Phys. Rev. B