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

Journal Article · Fri Jun 01 00:00:00 EDT 2012 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.85.214515· OSTI ID:1059740

Arham, H. Z.; Hunt, C. R.; Park, W. K.; Gillett, J.; Das, S. D.; Sebastian, S. E.; Xu, Z. J.; Wen, J. S.; Lin, Z. W.; Li, Q.; Gu, G.; Thaler, A.; Ran, S.; Bud'ko, S. L.; Canfield, P. C.; Chung, D. Y.; Kanatzidis, M. G.; Greene, L. H.

We use point-contact spectroscopy (PCS) to probe AEFe₂As₂ (AE=Ca,Sr,Ba) and Fe_1+yTe. For AE=Sr,Ba we detect orbital fluctuations above TS 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 Fe_1+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.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: DE-AC02-98CH10886
• OSTI ID: 1059740
• Report Number(s): BNL-98417-2012-JA; PRBMDO; R&D Project: PO-015; KC0202010
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 85, Issue 21; ISSN 1098-0121
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY