Defects from phonons: Atomic transport by concerted motion in simple crystalline metals
Artikel i vetenskaplig tidskrift, 2020

Point defects play a crucial role in crystalline materials as they do not only impact the thermodynamic properties but are also central to kinetic processes. While they are necessary in thermodynamic equilibrium spontaneous defect formation in the bulk is normally considered highly improbable except for temperatures close to the melting point. Here, we demonstrate by means of atomistic simulations that processes involving concerted atomic motion that give rise to defect formation are in fact frequent in body-centered cubic metals even down to about 50% of the melting temperature. It is shown that this behavior is intimately related to the anharmonicity of the lattice vibrations and a flat energy landscape along certain crystallographic directions, a feature that is absent in, e.g., face-centered cubic lattice structures. This insight has implications for our general understanding of these materials and furthermore provides a complementary explanation for the so-called anomalous diffusion in group 4 transition metals.

Författare

Erik Fransson

Chalmers, Fysik, Kondenserad materie- och materialteori

Paul Erhart

Chalmers, Fysik, Kondenserad materie- och materialteori

Acta Materialia

1359-6454 (ISSN)

Vol. 196 770-775

Ämneskategorier

Materialkemi

Metallurgi och metalliska material

Den kondenserade materiens fysik

DOI

10.1016/j.actamat.2020.06.040

Mer information

Senast uppdaterat

2020-09-28