First-order magnetic and structural phase transitions in Fe1+y Sex Te1-x

Shiliang Li, Clarina De La Cruz, Q. Huang, Y. Chen, J. W. Lynn, Jiangping Hu, Yi Lin Huang, Fong Chi Hsu, Kuo Wei Yeh, Maw Kuen Wu, Pengcheng Dai

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523 Scopus citations

Abstract

We use bulk magnetic susceptibility, electronic specific heat, and neutron scattering to study structural and magnetic phase transitions in Fe1+y Sex Te1-x. Fe1.068 Te exhibits a first-order phase transition near 67 K with a tetragonal-to-monoclinic structural transition and simultaneously develops a collinear antiferromagnetic (AF) order responsible for the entropy change across the transition. Systematic studies of the FeSe1-x Tex system reveal that the AF structure and lattice distortion in these materials are different from those of FeAs-based pnictides. These results call into question the conclusions of present density-functional calculations, where FeSe1-x Tex and FeAs-based pnictides are expected to have similar Fermi surfaces and therefore the same spin-density wave AF order.

Original languageEnglish
Article number054503
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume79
Issue number5
DOIs
StatePublished - Feb 2 2009

Funding

FundersFunder number
National Science Foundation
Directorate for Mathematical and Physical Sciences0756568, 0603759

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