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Condensed Matter Seminar: "Robust nematic state in electron-doped pnictides induced by isotropic quenched disorder"

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Thursday, February 25, 2016
11:30 am - 12:30 pm
Adriana Moreo (University of Tennessee, ORNL)
Condensed Matter Seminar

The phase diagram of electron-doped pnictides as a function of temperature, electronic density, and isotropic quenched disorder strength obtained by means of computational techniques applied to a three-orbital (xz, yz, xy) spin-fermion model with lattice degrees of freedom will be presented. In experiments, chemical doping introduces disorder but in theoretical studies the relationship between electronic doping and the randomly located dopants, with their associated quenched disorder, is difficult to address. The use of computational techniques allows to study independently the effects of electronic doping, regulated by a global chemical potential, and impurity disorder at randomly selected sites. Surprisingly, Monte Carlo simulations reveal that the fast reduction with doping of the N\'{e}el T_N and the structural T_S transition temperatures, and the concomitant stabilization of a robust nematic state, is primarily controlled by the magnetic dilution associated with the in-plane isotropic disorder introduced by Fe substitution. In the doping range considered, changes in the Fermi Surface produced by electron doping affect only slightly both critical temperatures. Comparisons with STM and neutron scattering experiments will be presented.

Ref: S. Liang, C. Bishop, A. Moreo, and E. Dagotto, Phys. Rev. B 92, 104512 (2015)

Contact: Cristin Paul