Lattice instabilities in metallic elements
2012 (English)In: Reviews of Modern Physics, ISSN 0034-6861, E-ISSN 1539-0756, Vol. 84, no 2, 945-986 p.Article in journal (Refereed) Published
Most metallic elements have a crystal structure that is either body-centered cubic (bcc), face-centered close packed, or hexagonal close packed. If the bcc lattice is the thermodynamically most stable structure, the close-packed structures usually are dynamically unstable, i.e., have elastic constants violating the Born stability conditions or, more generally, have phonons with imaginary frequencies. Conversely, the bcc lattice tends to be dynamically unstable if the equilibrium structure is close packed. This striking regularity essentially went unnoticed until ab initio total-energy calculations in the 1990s became accurate enough to model dynamical properties of solids in hypothetical lattice structures. After a review of stability criteria, thermodynamic functions in the vicinity of an instability, Bain paths, and how instabilities may arise or disappear when pressure, temperature, and/or chemical composition is varied are discussed. The role of dynamical instabilities in the ideal strength of solids and in metallurgical phase diagrams is then considered, and comments are made on amorphization, melting, and low-dimensional systems. The review concludes with extensive references to theoretical work on the stability properties of metallic elements.
Place, publisher, year, edition, pages
2012. Vol. 84, no 2, 945-986 p.
ab-initio calculations, electronic-structure calculations, structural phase-transitions, ideal tensile-strength, higher-energy phases, group-iv metals, tetragonal equilibrium states, shear-modulus instabilities, centered-cubic zirconium, high-pressure phases
IdentifiersURN: urn:nbn:se:kth:diva-98723DOI: 10.1103/RevModPhys.84.945ISI: 000304750900001ScopusID: 2-s2.0-84862132117OAI: oai:DiVA.org:kth-98723DiVA: diva2:539102
QC 201207032012-07-032012-07-022012-07-03Bibliographically approved