APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014;
Denver, Colorado
Session J40: Invited Session: Superconductivity and Magnetism of Iron-based Superconductors II
2:30 PM–5:30 PM,
Tuesday, March 4, 2014
Room: Mile High Ballroom 2B-3B
Sponsoring
Unit:
DCMP
Chair: Jeffrey W. Lynn, National Institute of Standards and Technology
Abstract ID: BAPS.2014.MAR.J40.3
Abstract: J40.00003 : Electron delocalization, orbital order, magnetism, and emergent superconductivity in Fe$_{1+y}$Te and Fe$_{1+y}$(Te,S/Se)
3:42 PM–4:18 PM
Preview Abstract
View Presentation
Abstract
Author:
Igor Zaliznyak
(Condensed Matter Physics and Material Science Department, Brookhaven National Laboratory)
Neutron scattering [1] reveales an unusual enhancement, on warming, of
dynamical magnetism in iron telluride, Fe$_{1+y}$Te, the non-superconducting
parent material of the chalcogenide family of iron-based superconductors,
and in nearly critical Fe$_{1+y}$Te$_{1-x}$(S,Se)$_{x}$, where bulk
measurements show the presence of filamentary superconductivity [2]. While
these findings are consistent with both Kondo-like screening of local spins
by conduction electrons, or a delocalization, on cooling, of one of the
electrons, our more recent results shed light on this issue, favoring the
latter scenario. Investigation of the magneto-structural phase diagram of
the Fe$_{1+y}$Te series revealed that the low-temperature phase, which
in the nearly stoichiometric (y $\approx $ 0) material is attained via the
first order phase transition at T$_{N} \quad \approx $ 70 K, is characterized
not only by antiferromagnetic and structural order, but also by a peculiar
type of orbital order. By combining results of bulk characterization of
electronic behavior and the diffraction data on the microscopic structural
changes for samples with y $\approx $ 0.05 to 0.13, we were able to
disentangle different low-temperature orders and identify new,
electronically driven ferro-orbital ordering transition. The newly
discovered orbital ordering is characterized by the formation of zigzag
Fe-Fe chains similar to those in manganites, and is associated with the
delocalization of one of the electrons. This has profound effect on magnetic
and electronic properties, including marked decrease of resistivity and
magnetic susceptibility.\\[4pt]
In collaboration with D. Fobes, Z. Zhu, R. Zhong, G. Gu, J. Tranquada, C. Petrovic, V. Solovyov, Condensed Matter Physics and Material Science Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA; A. Savici, M. Lumsden, M. Stone, and B. Winn, NSSD, Oak Ridge National Laboratory, Oak Ridge, TN. This work was supported by the US DOE under Contract DE-AC02-98CH10886.
\\[4pt]
[1] I. A. Zaliznyak, Z. J. Xu, J. M. Tranquada, G. D. Gu, A. M. Tsvelik, M.
B. Stone, Phys. Rev. Lett. 107, 216403 (2011).
\\[0pt]
[2] Rongwei Hu, E. S. Bozin, J. B. Warren, C. Petrovic, Phys. Rev. B 80,
214514 (2009).\\[0pt]
[3] I. A. Zaliznyak, Z. J. Xu, J. S. Wen, J. M. Tranquada, G. D. Gu, V.
Solovyov, V. N. Glazkov, A. I. Zheludev, V. O. Garlea, M. B. Stone, Phys.
Rev. B 85, 085105 (2012); also unpublished (2014).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.J40.3