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arXiv · 0902.1481

Quantum oscillations in antiferromagnetic CaFe2As2 on the brink of superconductivity

N. Harrison·R. D. McDonald·C. H. Mielke·E. D. Bauer·F. Ronning·J. D. Thompson
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Abstract

We report quantum oscillation measurements on CaFe2As2 under strong magnetic fields- recently reported to become superconducting under pressures of as little as a kilobar. The largest observed carrier pocket occupies less than 0.05 % of the paramagnetic Brillouin zone volume- consistent with Fermi surface reconstruction caused by antiferromagnetism. On comparing several alkali earth AFe2As2 antiferromagnets (with A=Ca,Sr and Ba), the dependence of both the Fermi surface cross-sectional area F_alpha and the effective mass m*_alpha of the primary observed pocket on the antiferromagnetic/structural transition temperature T_s is found to be consistent with quasiparticles in a conventional spin-density wave model. These findings suggest that a conventional spin-density wave exists within close proximity to superconductivity in this series of compounds, which may have implications for the microscopic origin of unconventional pair formation.

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N. Harrison, R. D. McDonald, C. H. Mielke, E. D. Bauer, F. Ronning, J. D. Thompson. 2009-02-09. Quantum oscillations in antiferromagnetic CaFe2As2 on the brink of superconductivity. https://arxiv.org/abs/0902.1481

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