Elastic and phonon properties of FeSi and CoSi in the B2 structure

Acun, Alev Duygu; Soyalp, F.

doi:10.1080/14786435.2011.617323

Cited by 6 publications

(5 citation statements)

References 34 publications

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“…The Fe-Si interactions represent a challenge to study, given the discrepancies in the elastic and structural results obtained by the references. ,− , Our calculations for the B2 structure show stiffness constants inside the range set by first-principles calculations but with a slightly lower lattice constant. The ternary potential exhibited discrepancies when calculating Fe-Si B20 properties, showing a much lower lattice constant and overestimating C 11 and C 12 .…”

Section: Potential Developmentmentioning

confidence: 79%

“…In this study, the primary reference structure for Fe-Si was defined as Cs-Cl, that is, the B2 structure. There are also reports on Fe-Si with B2 and Na-Cl-like B1 structures and an experimentally observed B20, featuring a relatively low internal symmetry. ,− However, the reported results are not consistent and present significant discrepancies. Thus, we decided to adopt the B2 (ordered BCC) structure because the Fe-Cr-Si system with a low Si content is known to array in a BCC structure.…”

Section: Potential Developmentmentioning

confidence: 87%

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A Modified Embedded-Atom Potential for Fe-Cr-Si Alloys

et al. 2021

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We developed a modified embedded atom method (MEAM) potential for Fe-Cr-Si ternary systems. These alloys have superior corrosion and crack resistance, making them candidate materials for several engineering applications such as accidenttolerant fuel cladding. We used a multiobjective optimization approach to match Fe-Cr-Si's elastic constants, ground-state energies, and structural parameters with ab initio calculations. The potential has been parameterized by fitting to a set of literature values obtained using density functional theory (DFT) or experimental studies. The developed potential was used in molecular dynamics (MD) simulations to extract mechanical and thermal properties. We obtained the calculated elastic constants for Fe-Cr-Si binary interactions using the proposed potential, agreeing with ab initio calculations. Our calculated self-diffusion coefficient values and defect formation energy using this potential are in good agreement with the previous literature. Therefore, the developed potential can investigate the fundamental behaviors on an atomic scale under harsh conditions like elevated temperature and irradiation.

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Section: Potential Developmentmentioning

confidence: 79%

Section: Potential Developmentmentioning

confidence: 87%

A Modified Embedded-Atom Potential for Fe-Cr-Si Alloys

et al. 2021

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“…A plausible reason this transition was not observed in previous experiments could be a large kinetic barrier. Furthermore, previous works , showed that the structures of FeSi with their competing stability are sensitive to the composition and experimental environment. To evaluate the effect of nonhydrostatic stress as a driving force of the kinetic phase-transition process, we have carried out first-principles calculations to assess the energetic and kinetic aspects associated with the pressure and strain effects on the B20–B2 phase transition of FeSi.…”

Section: Resultsmentioning

confidence: 99%

Effect of Pressure on Crystal Structure and Phonon Density of States of FeSi

Kumar,

Liu,

et al. 2024

J. Phys. Chem. C

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The strongly correlated material FeSi displays several unusual thermal, magnetic, and structural properties under varying pressure–temperature (P–T) conditions. It is a potential thermoelectric alloy and a material with several geochemical implications as a possible constituent at the Earth’s core-mantle boundary (CMB). Previous theoretical studies predicted a pressure-induced B20–B2 transition at ambient temperature below 40 GPa; however, experimentally, the structural transition is observed only under high P–T conditions. In this study, we have performed high-pressure powder X-ray diffraction (XRD) up to 90 GPa and Nuclear Resonant Inelastic X-ray Scattering (NRIXS) measurements up to 120 GPa to understand the phase stability and lattice dynamics. Our study provides evidence for a nonhydrostatic stress-induced B20–B2 transition in FeSi at around 36 GPa. We deduced the Fe partial phonon density of states (PDOS) and thermal parameters from NRIXS measurements up to 120 GPa and compared them with density functional theory (DFT) calculations. Additionally, the computations show pressure-induced metallization and band gap closing at around 12 GPa.

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“…NiSi (Franciosi et al, 1982 ; Lee et al, 2000 ; Detavernier et al, 2003 ; Jin et al, 2013 ), FeSi (Damascelli et al, 1997a , b ), CoSi (Acun and Soyalp, 2012 ), and similar compounds (Kim, 2015 ) have been extensively studied with above applications in mind, and also for their various unusual physical and chemical properties (Weber et al, 2006 ; Lin et al, 2015 ; Geenen et al, 2018 ). NiSi (Connétable and Thomas, 2009 ) is structurally similar to NiGe.…”

Section: Introductionmentioning

confidence: 99%

Phonons and Thermal Expansion Behavior of NiSi and NiGe

et al. 2018

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We have carried out first principles calculations of the vibrational and thermodynamic behavior in NiSi and isostructural compound NiGe. Phonon density of states has also been measured in NiSi using inelastic neutron scattering techniques. We find that the vibrational spectra of the two compounds are very different, due to the difference in the size and mass of Si and Ge. Interesting anomalous thermal behavior of NiSi due to anharmonic phonons is brought out well in our calculations, particularly the negative thermal expansion (NTE) along the b-axis of the orthorhombic unit cell. Large difference in thermal expansion behavior of NiSi and NiGe is very well reproduced by the calculations. Additionally, calculations enable to identify the phonon modes which lend major contribution to the negative thermal expansion behavior in NiSi, and reasons for negligible NTE in NiGe. Such typical representative modes at the zone-boundary along b-axis involve transverse vibrations of Si/Ge along c-axis.PACS numbers: 78.70.Nx, 63.20.-e, 65.40.–b.

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Elastic and phonon properties of FeSi and CoSi in the B2 structure

Cited by 6 publications

References 34 publications

A Modified Embedded-Atom Potential for Fe-Cr-Si Alloys

A Modified Embedded-Atom Potential for Fe-Cr-Si Alloys

Effect of Pressure on Crystal Structure and Phonon Density of States of FeSi

Phonons and Thermal Expansion Behavior of NiSi and NiGe

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