title: Fermi-surface reconstruction and complex phase equilibria in CaFe2As2.
abstract: Fermi-surface topology governs the relationship between magnetism and superconductivity in iron-based materials. Using low-temperature transport, angle-resolved photoemission, and x-ray diffraction, we show unambiguous evidence of large Fermi-surface reconstruction in CaFe2As2 at magnetic spin-density-wave and nonmagnetic collapsed-tetragonal (cT) transitions. For the cT transition, the change in the Fermi-surface topology has a different character with no contribution from the hole part of the Fermi surface. In addition, the results suggest that the pressure effect in CaFe2As2 is mainly leading to a rigid-band-like change of the valence electronic structure. We discuss these results and their implications for magnetism and superconductivity in this material.
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: K
authors.initials: K
authors.lastname: Gofryk
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: B
authors.initials: B
authors.lastname: Saparov
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: T
authors.initials: T
authors.lastname: Durakiewicz
authors.affiliation: Department of Physics, St. Petersburg State University, St. Petersburg 198504, Russia and Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Chikina
authors.affiliation: Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Danzenbächer
authors.affiliation: Department of Physics, St. Petersburg State University, St. Petersburg 198504, Russia and Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
authors.forename: D V
authors.initials: DV
authors.lastname: Vyalikh
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Graf
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: A S
authors.initials: AS
authors.lastname: Sefat