Dramatic changes in the electronic structure upon transition to the collapsed tetragonal phase in CaFe₂As₂

Journal Article · Fri Jan 31 04:00:00 EST 2014 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.89.020511· OSTI ID:1136867

Dhaka, R. S. ^[1]; Jiang, Rui ^[1]; Ran, S. ^[1]; Budko, Sergey L. ^[1]; Canfield, Paul C. ^[1]; Harmon, Bruce N. ^[1]; Kaminski, Adam ^[1]; Tomic, Milan ^[2]; Valenti, Roser ^[2]; Lee, Yongbin ^[1]

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1. Ames Lab., Ames, IA (United States)
2. Goethe Univ., Frankfurt (Germany)

We use angle-resolved photoemission spectroscopy and density functional theory calculations to study the electronic structure of CaFe₂As₂ in the collapsed tetragonal (CT) phase. This unusual phase of iron arsenic high-temperature superconductors was hard to measure as it exists only under pressure. By inducing internal strain, via the postgrowth thermal treatment of single crystals, we were able to stabilize the CT phase at ambient pressure. We find significant differences in the Fermi surface topology and band dispersion data from the more common orthorhombic-antiferromagnetic or tetragonal-paramagnetic phases, consistent with electronic structure calculations. The top of the hole bands sinks below the Fermi level, which destroys the nesting present in parent phases. The absence of nesting in this phase, along with an apparent loss of Fe magnetic moment, are now clearly experimentally correlated with the lack of superconductivity in this phase.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-07CH11358
• OSTI ID: 1136867
• Report Number(s): IS--J 8266
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 02 Vol. 89; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE