Chemically Mediated Quantum Criticality in NbFe(2)

TitleChemically Mediated Quantum Criticality in NbFe(2)
Publication TypeJournal Article
Year of Publication2011
AuthorsAlam A, Johnson DD
Journal TitlePhysical Review Letters
Date Published11
Type of ArticleArticle
ISBN Number0031-9007
Accession NumberWOS:000297131300003
Keywordsalloys, total-energy

Laves-phase Nb(1+c)Fe(2-c) is a rare itinerant intermetallic compound exhibiting magnetic quantum criticality at c(cr) similar to 1: 5% Nb excess; its origin, and how alloying mediates it, remains an enigma. For NbFe(2), we show that an unconventional band critical point above the Fermi level E(F) explains most observations and that chemical alloying mediates access to this unconventional band critical point by an increase in EF with decreasing electrons (increasing % Nb), counter to rigid-band concepts. We calculate that EF enters the unconventional band critical point region for c(cr) > 1.5% Nb and by 1.74% Nb there is no Nb site-occupation preference between symmetry-distinct Fe sites, i.e., no electron-hopping disorder, making resistivity near constant as observed. At larger Nb (Fe) excess, the ferromagnetic Stoner criterion is satisfied.

Alternate JournalPhys. Rev. Lett.