Current materials-related calculations employ density-functional theory (DFT), commonly using the (semi-)local-density approximations for the exchange-correlation (xc) functional. The difficulties in arriving at a reasonable description of van der Waals (vdW) interactions by DFT-based models is to date a big challenge. In this work, we use various flavors of vdW-corrected DFT xc functionals - ranging from the quasiempirical force-field add-on vdW corrections to self-consistent nonlocal correlation functionals - to study the bulk lattice and mechanical properties (including the elastic constants and anisotropic indices) of the coinage metals (copper, silver, and gold). We critically assess the reliability of the different vdW-corrected DFT methods in describing their anisotropic mechanical properties which have been less reported in the literature. In the context of this work, we regard that our results reiterate the fact that advocating a so-called perfect vdW-inclusive xc functional for describing the general physics and chemistry of these coinage metals could be a little premature. These challenges to modern-day functionals for anisotropically strained coinage metals (e.g., at the faceted surfaces of nanostructures) may well be relevant to other strained material systems.
Bibliographical noteFunding Information:
The authors acknowledge the support of National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science, and Technology (NRF Grant No. 2014R1A1A1003415) and the providing of computational resources by the Korean Institute of Science and Technology Information (KISTI) supercomputing center through the strategic support program for supercomputing application research (KSC-2015-C3-043). We thank J. W. Park for the helpful discussion regarding the use of vdW corrections in the vasp code and Y. G. Jung for helping in the data organization and discussion of this paper.
© 2016 American Physical Society.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics