title: Strong cooperative coupling of pressure-induced magnetic order and nematicity in FeSe.
abstract: A hallmark of the iron-based superconductors is the strong coupling between magnetic, structural and electronic degrees of freedom. However, a universal picture of the normal state properties of these compounds has been confounded by recent investigations of FeSe where the nematic (structural) and magnetic transitions appear to be decoupled. Here, using synchrotron-based high-energy x-ray diffraction and time-domain Mössbauer spectroscopy, we show that nematicity and magnetism in FeSe under applied pressure are indeed strongly coupled. Distinct structural and magnetic transitions are observed for pressures between 1.0 and 1.7 GPa and merge into a single first-order transition for pressures ≳1.7 GPa, reminiscent of what has been found for the evolution of these transitions in the prototypical system Ba(Fe1-xCox)2As2. Our results are consistent with a spin-driven mechanism for nematic order in FeSe and provide an important step towards a universal description of the normal state properties of the iron-based superconductors.
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: K
authors: K
authors: Kothapalli
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.
authors: A E
authors: AE
authors: Böhmer
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: W T
authors: WT
authors: Jayasekara
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: B G
authors: BG
authors: Ueland
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: P
authors: P
authors: Das
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: A
authors: A
authors: Sapkota
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.
authors: V
authors: V
authors: Taufour
authors: HPCAT, Carnegie Institute of Washington, Argonne, Illinois 60439, USA.
authors: Y
authors: Y
authors: Xiao
authors: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors: E
authors: E
authors: Alp
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: S L
authors: SL
authors: Bud'ko
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: P C
authors: PC
authors: Canfield
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: A
authors: A
authors: Kreyssig
authors: Division of Materials Sciences and Engineering, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
authors: A I
authors: AI
authors: Goldman