title: Ferro-orbital ordering transition in iron telluride Fe(1+y)Te.
abstract: Fe(1+y)Te with y≲0.05 exhibits a first-order phase transition on cooling to a state with a lowered structural symmetry, bicollinear antiferromagnetic order, and metallic conductivity, dρ/dT>0. Here, we study samples with y=0.09(1), where the frustration effects of the interstitial Fe decouple different orders, leading to a sequence of transitions. While the lattice distortion is closely followed by incommensurate magnetic order, the development of bicollinear order and metallic electronic coherence is uniquely associated with a separate hysteretic first-order transition, at a markedly lower temperature, to a phase with dramatically enhanced bond-order wave (BOW) order. The BOW state suggests ferro-orbital ordering, where electronic delocalization in ferromagnetic zigzag chains decreases local spin and results in metallic transport.
authors.affiliation: CMPMSD, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: David
authors.initials: D
authors.lastname: Fobes
authors.affiliation: CMPMSD, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Igor A
authors.initials: IA
authors.lastname: Zaliznyak
authors.affiliation: CMPMSD, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Xu
authors.affiliation: CMPMSD, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Ruidan
authors.initials: R
authors.lastname: Zhong
authors.affiliation: CMPMSD, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Genda
authors.initials: G
authors.lastname: Gu
authors.affiliation: CMPMSD, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Tranquada
authors.affiliation: NCNR, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: Leland
authors.initials: L
authors.lastname: Harriger
authors.affiliation: NCNR, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: Deepak
authors.initials: D
authors.lastname: Singh
authors.affiliation: QCMD, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: V Ovidiu
authors.initials: VO
authors.lastname: Garlea
authors.affiliation: QCMD, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Lumsden
authors.affiliation: QCMD, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Barry
authors.initials: B
authors.lastname: Winn