Nematic Electronic Structure in the "Parent" State of the Iron-Based Superconductor Ca(Fe1-xCox)2As2

T.-M. Chuang, Milan Peter Allan, Jinho Lee, Yang Xie, Ni Ni, S. L. Bud'ko, G. S. Boebinger, P. C. Canfield, Seamus Davis

Research output: Contribution to journalArticlepeer-review

440 Citations (Scopus)

Abstract

The mechanism of high-temperature superconductivity in the newly discovered iron-based superconductors is unresolved. We use spectroscopic imaging-scanning tunneling microscopy to study the electronic structure of a representative compound CaFe1.94Co0.06As2 in the "parent" state from which this superconductivity emerges. Static, unidirectional electronic nanostructures of dimension eight times the inter-iron-atom distance a(Fe-Fe) and aligned along the crystal a axis are observed. In contrast, the delocalized electronic states detectable by quasiparticle interference imaging are dispersive along the b axis only and are consistent with a nematic alpha2 band with an apparent band folding having wave vector (q) over right arrow congruent to +/- 22 pi/8a(Fe-Fe) along the a axis. All these effects rotate through 90 degrees at orthorhombic twin boundaries, indicating that they are bulk properties. As none of these phenomena are expected merely due to crystal symmetry, underdoped ferropnictides may exhibit a more complex electronic nematic state than originally expected.

Original languageEnglish
Pages (from-to)181-184
Number of pages4
JournalScience
Volume327
Issue number5962
DOIs
Publication statusPublished - 8 Jan 2010

Keywords

  • MOTT INSULATOR
  • PHASES

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