Role of fluorine in the iron pnictides: phonon softening and effective hole-doping

ORAL

Abstract

Using first principles techniques, we investigate the influence of fluorine doping on the electronic structure, lattice dynamics and electron-phonon coupling in LaFeAsO. We explicitly simulate the F-doping using a supercell model in order to explore properties not described by virtual crystal models. Our analysis reveals that local lattice relaxation accompanies the fluorine doping and modifies the lattice dynamics, in accord with recent experimental data. In addition, it is found that the charge density of the doped electrons cannot be described by simplified models of electron-doping in the two-dimensional Fe-plane.

*This work was supported by National Science Foundation Grant No. DMR07-05941, the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Computational resources have been provided by DOE at Lawrence Berkeley National Laboratory's NERSC facility.

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Authors

  • Jesse Noffsinger

    • UC Berkeley, Lawrence Berkeley National Labratory

  • Feliciano Giustino

    • UC Berkeley, Lawrence Berkeley National Labratory

  • Steven G. Louie

    • The department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory
    • UC Berkeley, Lawrence Berkeley National Labratory
    • University of California Berkeley
    • Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
    • Department of Physics, University of California, Berkeley and Lawrence Berkeley National Laboratory
    • Department of Physics, University of California at Berkeley and Materials Sciences Division of Lawrence Berkeley National Laboratory
    • University of California, Berkeley
    • University of California at Berkeley and Lawrence Berkeley National Lab

  • Marvin L. Cohen

    • The department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory
    • UC Berkeley, Lawrence Berkeley National Labratory
    • University of California Berkeley
    • Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
    • Department of Physics, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory
    • Department of Physics, University of California at Berkeley and Materials Sciences Division of Lawrence Berkeley National Laboratory
    • Physics Dept, UC Berkeley
    • University of California, Berkeley and MSD, Lawrence Berkeley National Laboratory