Title:	Ab initio study of correlated Fe-based alloys
DNr:	SNIC 2015/1-409
Project Type:	SNIC Medium Compute
Principal Investigator:	Leonid Poyurovskiy <leonid@cpht.polytechnique.fr>
Affiliation:	Linköpings universitet
Duration:	2015-11-30 – 2016-12-01
Classification:	10304
Keywords:

Abstract

This project will be continuation of the work carried out under snic 001-11-125, snic 001-12-160, snic 001/12-195, snic 2013/1-226 and snic 2014/1-327 in investigating properties of correlated transition-metal and rare-earth-based compounds with an advanced first-principles theoretical method based on the dynamical mean-field theory (DMFT). In the framework of those projects we have calculated properties of different phases of iron as well as various heavy fermion materials. The work on transition metals resulted in several publications clarifying the role of electronic correlations in the physics of elemental Fe and Os as well as in NiFe alloys at extreme conditions. The study of Ce-based heavy-fermions has clarified the evolution of their electronic structure under pressure, in particular, in "122" and CeNiXO (X=As,P) famlilies. The results of those calculations were pbulished in a number of papers, in particular, Pourovskii et al. PRL 112, 106407 (2014), Ren et al. PRX 4, 031055 (2014), Luo et al. Nature Mat. 13 777 (2014), Pourovskii et al. PRB 90 155 120 (2014), Vekilova et al. PRB 91, 245116 (2015), Dubrovinsky et al. Nature 525 226 (2015) were published during last two years. In the framework of the present project we plan to continue and extend this work. In particular, we are going to study more complex Fe-Rh and Fe-Mn alloys. The stoichometric FeRh alloy features a poorly understood transition from the low-T antiferromagnetic (AFM) to high-temperature ferromagnetic (FM) phases. This transition seems to be hard to explain within the standard DFT framework. A sharp drop in the resistivity at the transition temperature also points to probable dramatic reduction in electronic correlations in the FM phase as compared to the AFM one. The iron-rich bcc Fe-Mn alloy features an interesting transition from the FM to AFM alignment of Mn and Fe spins as a function of Mn concentration. We plan to study the evoluiton of relative stability of FM vs. AFM and strenght of correlation effects in those two phase as a function of Mn concentration. We will also study the impact of correlations on the mono-vacancy formation energy in ferro- and paramagnetic bcc-Fe.