Hidden scale invariance of metals
- Author(s)
- Felix Hummel, Georg Kresse, Jeppe C. Dyre, Ulf R. Pedersen
- Abstract
Density functional theory (DFT) calculations of 58 liquid elements at their triple point show that most metals exhibit near proportionality between the thermal fluctuations of the virial and the potential energy in the isochoric ensemble. This demonstrates a general "hidden" scale invariance of metals making the condensed part of the thermodynamic phase diagram effectively one dimensional with respect to structure and dynamics. DFT computed density scaling exponents, related to the Grüneisen parameter, are in good agreement with experimental values for the 16 elements where reliable data were available. Hidden scale invariance is demonstrated in detail for magnesium by showing invariance of structure and dynamics. Computed melting curves of period three metals follow curves with invariance (isomorphs). The experimental structure factor of magnesium is predicted by assuming scale invariant inverse power-law (IPL) pair interactions. However, crystal packings of several transition metals (V, Cr, Mn, Fe, Nb, Mo, Ta, W, and Hg), most post-transition metals (Ga, In, Sn, and Tl), and the metalloids Si and Ge cannot be explained by the IPL assumption. The virial-energy correlation coefficients of iron and phosphorous are shown to increase at elevated pressures. Finally, we discuss how scale invariance explains the Grüneisen equation of state and a number of well-known empirical melting and freezing rules.
- Organisation(s)
- Computational Materials Physics
- External organisation(s)
- Roskilde University, Technische Universität Wien
- Journal
- Physical Review B
- Volume
- 92
- No. of pages
- 12
- ISSN
- 1098-0121
- DOI
- https://doi.org/10.1103/PhysRevB.92.174116
- Publication date
- 11-2015
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103025 Quantum mechanics, 103036 Theoretical physics, 103015 Condensed matter, 103009 Solid state physics
- Keywords
- ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials, Condensed Matter Physics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/81a06511-a836-4510-a087-069fee9c82f8