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Detection of orbital fluctuations above the structural transition temperature in the iron pnictides and chalcogenides

TitleDetection of orbital fluctuations above the structural transition temperature in the iron pnictides and chalcogenides
Publication TypeJournal Article
Year of Publication2012
AuthorsArham HZ, Hunt CR, Park WK, Gillett J, Das SD, Sebastian SE, Xu ZJ, Wen JS, Lin ZW, Li Q, Gu G, Thaler A, Ran S, Bud'ko SL, Canfield PC, Chung DY, Kanatzidis MG, Greene LH
Journal TitlePhysical Review B
Volume85
Pages214515
Date Published06
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000305529700003
Keywordsanisotropy, density, detwinned ba(fe1-xcox)(2)as-2, metals, POINT-CONTACT SPECTROSCOPY, superconductivity, symmetry
Abstract

We use point-contact spectroscopy (PCS) to probe AEFe(2)As(2) (AE = Ca, Sr, Ba) and Fe1+yTe. For AE = Sr, Ba we detect orbital fluctuations above T-S while for AE = Ca these fluctuations start below T-S. Co doping preserves the orbital fluctuations while K doping suppresses it. The fluctuations are only seen at those dopings and temperatures where an in-plane resistive anisotropy is known to exist. We predict an in-plane resistive anisotropy of Fe1+yTe above T-S. Our data are examined in light of the recent work by Lee and Phillips (arXiv:1110.5917v2). We also study how joule heating in the PCS junctions impacts the spectra. Spectroscopic information is only obtained from those PCS junctions that are free of heating effects while those PCS junctions that are in the thermal regime display bulk resistivity phenomena.
URL<Go to ISI>://WOS:000305529700003
DOI10.1103/PhysRevB.85.214515
Alternate JournalPhys. Rev. B