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Title: Effects of temperature and pressure on phonons in FeSi1–xAlx

The effects of temperature and pressure on phonons in B20 compounds FeSi1–xAlx were measured using inelastic neutron scattering and nuclear-resonant inelastic x-ray scattering. The effect of hole doping through Al substitution is compared to results of alloying with Co (electron doping) in Fe₁₋xCoxSi. While the temperature dependence of phonons in FeSi is highly anomalous, doping with either type of carriers leads to a recovery of the normal quasiharmonic behavior. Density functional theory (DFT) computations of the electronic band structure and phonons were performed. The anomaly in the temperature dependence of the phonons in undoped FeSi was related to the narrow band gap, and its sensitivity to the effect of thermal disordering by phonons. On the other hand, the pressure dependence of phonons at room temperature in undoped FeSi follows the quasiharmonic behavior and is well reproduced by the DFT calculations.
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Publication Date:
Publisher's Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 87; Journal Issue: 18; Related Information: CHORUS Timestamp: 2017-04-06 12:29:37; Journal ID: ISSN 1098-0121
American Physical Society
Sponsoring Org:
Country of Publication:
United States
OSTI Identifier: