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Title: Heavy-impurity resonance, hybridization, and phonon spectral functions in Fe 1-xM xSi, M=Ir,Os

Abstract

The vibrational behavior of heavy substitutional impurities (M=Ir,Os) in Fe 1-xM xSi (x = 0, 0.02, 0.04, 0.1) was investigated with a combination of inelastic neutron scattering (INS), transport measurements, and first-principles simulations. In this paper, our INS measurements on single-crystals mapped the four-dimensional dynamical structure factor, S(Q;E), for several compositions and temperatures. Our results show that both Ir and Os impurities lead to the formation of a weakly dispersive resonance vibrational mode, in the energy range of the acoustic phonon dispersions of the FeSi host. We also show that Ir doping, which introduces free carriers and increases electron-phonon coupling, leads to softened interatomic force-constants compared to doping with Os, which is isoelectronic to Fe. We analyze the phonon S(Q,E) from INS through a Green's function model incorporating the phonon self-energy based on first-principles density functional theory (DFT) simulations. Calculations of the quasiparticle spectral functions in the doped system reveal the hybridization between the resonance and the acoustic phonon modes. Finally, our results demonstrate a strong interaction of the host acoustic dispersions with the resonance mode, likely leading to the large observed suppression in lattice thermal conductivity.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1265677
Alternate Identifier(s):
OSTI ID: 1180388
Grant/Contract Number:
AC05-00OR22725; SC0001299; AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 91; Journal Issue: 9; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Delaire, O., Al-Qasir, Iyad I., May, Andrew F., Sales, Brian C., Niedziela, Jennifer L., Ma, Jie, Matsuda, Masaaki, Abernathy, Douglas L., and Berlijn, Tom. Heavy-impurity resonance, hybridization, and phonon spectral functions in Fe1-xMxSi, M=Ir,Os. United States: N. p., 2015. Web. doi:10.1103/PhysRevB.91.094307.
Delaire, O., Al-Qasir, Iyad I., May, Andrew F., Sales, Brian C., Niedziela, Jennifer L., Ma, Jie, Matsuda, Masaaki, Abernathy, Douglas L., & Berlijn, Tom. Heavy-impurity resonance, hybridization, and phonon spectral functions in Fe1-xMxSi, M=Ir,Os. United States. doi:10.1103/PhysRevB.91.094307.
Delaire, O., Al-Qasir, Iyad I., May, Andrew F., Sales, Brian C., Niedziela, Jennifer L., Ma, Jie, Matsuda, Masaaki, Abernathy, Douglas L., and Berlijn, Tom. Tue . "Heavy-impurity resonance, hybridization, and phonon spectral functions in Fe1-xMxSi, M=Ir,Os". United States. doi:10.1103/PhysRevB.91.094307. https://www.osti.gov/servlets/purl/1265677.
@article{osti_1265677,
title = {Heavy-impurity resonance, hybridization, and phonon spectral functions in Fe1-xMxSi, M=Ir,Os},
author = {Delaire, O. and Al-Qasir, Iyad I. and May, Andrew F. and Sales, Brian C. and Niedziela, Jennifer L. and Ma, Jie and Matsuda, Masaaki and Abernathy, Douglas L. and Berlijn, Tom},
abstractNote = {The vibrational behavior of heavy substitutional impurities (M=Ir,Os) in Fe1-xMxSi (x = 0, 0.02, 0.04, 0.1) was investigated with a combination of inelastic neutron scattering (INS), transport measurements, and first-principles simulations. In this paper, our INS measurements on single-crystals mapped the four-dimensional dynamical structure factor, S(Q;E), for several compositions and temperatures. Our results show that both Ir and Os impurities lead to the formation of a weakly dispersive resonance vibrational mode, in the energy range of the acoustic phonon dispersions of the FeSi host. We also show that Ir doping, which introduces free carriers and increases electron-phonon coupling, leads to softened interatomic force-constants compared to doping with Os, which is isoelectronic to Fe. We analyze the phonon S(Q,E) from INS through a Green's function model incorporating the phonon self-energy based on first-principles density functional theory (DFT) simulations. Calculations of the quasiparticle spectral functions in the doped system reveal the hybridization between the resonance and the acoustic phonon modes. Finally, our results demonstrate a strong interaction of the host acoustic dispersions with the resonance mode, likely leading to the large observed suppression in lattice thermal conductivity.},
doi = {10.1103/PhysRevB.91.094307},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 9,
volume = 91,
place = {United States},
year = {Tue Mar 31 00:00:00 EDT 2015},
month = {Tue Mar 31 00:00:00 EDT 2015}
}

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Cited by: 12 works
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