Novel Fe-Based Superconductor LaFe2As2 in Comparison with Traditional Pnictides

I. I. Mazin, Makoto Shimizu, Nayuta Takemori, Harald O. Jeschke

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

The recently discovered Fe-based superconductor (FeBS) LaFe2As2 seems to break away from an established pattern that doping an FeBS beyond 0.2e/Fe destroys superconductivity. LaFe2As2 has an apparent doping of 0.5e, yet superconducts at 12.1 K. Its Fermi surface bears no visual resemblance with the canonical FeBS fermiology. It also exhibits two phases, none magnetic and only one superconducting. We show that the difference between them nonetheless has a magnetic origin, the one featuring disordered moments, and the other locally nonmagnetic. We find that La there assumes an unusual valence of +2.6 to +2.7, so that the effective doping is reduced to 0.30-0.35e. A closer look reveals the same key elements: hole Fermi surfaces near Γ-Z and electron ones near the X-P lines, with the corresponding peak in susceptibility, and a strong tendency to stripe magnetism. The physics of LaFe2As2 is thus more similar to the FeBS paradigm than hitherto appreciated.

Original languageEnglish
Article number267001
JournalPhysical Review Letters
Volume123
Issue number26
DOIs
Publication statusPublished - Dec 31 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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