The interplanar bond strength in graphite has been identified to be very low, owing to the contribution of the van der Waals interaction. However, in this study, we use microscopic picosecond ultrasound to demonstrate that the elastic constant, C33, along the c axis of defect-free monocrystalline graphite exceeds 45 GPa, which is higher than reported values by 20%. Based on the experimental finding, we find that the LDA +U +RPA method, including both random phase approximation correlation and short-range correlation in 2 p Wannier orbitals, can be a promising solution. The agreement of thus calculated stiffness with the observation indicates non-negligible electron correlation effects with respect to both the short-range and long-range interactions.
Physical Review Materials
- Pub Date:
- April 2020
- Condensed Matter - Materials Science;
- Condensed Matter - Mesoscale and Nanoscale Physics;
- Physics - Computational Physics
- (Main text) 5 pages, 3 figures, (Supplementary material A) 2 pages, 2 figures, (Supplementary material B) 12 pages, 1 figure