Electronic correlations in Fe at Earths inner core conditions: Effects of alloying with Ni
2015 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 91, no 24, 245116- p.Article in journal (Refereed) Published
We have studied the body-centered cubic (bcc), face-centered cubic (fcc), and hexagonal close-packed (hcp) phases of Fe alloyed with 25 at.% of Ni at Earths core conditions using an ab initio local density approximation + dynamical mean-field theory approach. The alloys have been modeled by ordered crystal structures based on the bcc, fcc, and hcp unit cells with the minimum possible cell size allowing for the proper composition. Our calculations demonstrate that the strength of electronic correlations on the Fe 3d shell is highly sensitive to the phase and local environment. In the bcc phase, the 3d electrons at the Fe site with Fe only nearest neighbors remain rather strongly correlated, even at extreme pressure-temperature conditions, with the local and uniform magnetic susceptibility exhibiting a Curie-Weiss-like temperature evolution and the quasiparticle lifetime Gamma featuring a non-Fermi-liquid temperature dependence. In contrast, for the corresponding Fe site in the hcp phase, we predict a weakly correlated Fermi-liquid state with a temperature-independent local susceptibility and a quadratic temperature dependence of Gamma. The iron sites with nickel atoms in the local environment exhibit behavior in the range between those two extreme cases, with the strength of correlations gradually increasing along the hcp-fcc-bcc sequence. Further, the intersite magnetic interactions in the bcc and hcp phases are also strongly affected by the presence of Ni nearest neighbors. The sensitivity to the local environment is related to modifications of the Fe partial density of states due to mixing with Ni 3d states.
Place, publisher, year, edition, pages
American Physical Society , 2015. Vol. 91, no 24, 245116- p.
IdentifiersURN: urn:nbn:se:liu:diva-119789DOI: 10.1103/PhysRevB.91.245116ISI: 000355721300007OAI: oai:DiVA.org:liu-119789DiVA: diva2:827271
Funding Agencies|HPC-Europa2; Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST "MISiS" [K3-2015-038]; PHD DALEN [26228RM]; Swedish Research Council (VR) [621-2011-4426, 2011-42-59, 2014-4750]; Linkoping Linnaeus Initiative for Novel Functional Materials (LiLi-NFM); Swedish Foundation for Strategic Research (SSF) program [SRL10-0026]; Swedish Government Strategic Research Area Grant in Materials Science "Advanced Functional Materials" (AFM); Swedish e-Science Research Centre (SeRC); Ministry of Education and Science of the Russian Federation [14.Y26.31.0005]2015-06-262015-06-262015-06-26