%0 Journal Article
%T Ferro-orbital ordering transition in iron telluride Fe$_{1+y}$Te
%A David Fobes
%A Igor A. Zaliznyak
%A Zhijun Xu
%A Ruidan Zhong
%A Genda Gu
%A John M. Tranquada
%A Leland Harriger
%A Deepak Singh
%A V. Ovidiu Garlea
%A Mark Lumsden
%A Barry Winn
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevLett.112.187202
%X Fe$_{1+y}$Te with $y \lesssim 0.05$ exhibits a first-order phase transition on cooling to a state with a lowered structural symmetry, bicollinear antiferromagnetic order, and metallic conductivity, $d\rho/dT > 0$. 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 \emph{incommensurate} magnetic order, the development of \emph{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.
%U http://arxiv.org/abs/1307.7162v2