Theoretical investigations of NiTiSn and CoVSn compounds

Hichour, M.; Rached, D.; Khenata, R.; Rabah, M.; Merabet, M.; Reshak, A.H.; Omran, S. Bin; Abdiche, A.

doi:10.1016/j.jpcs.2012.03.014

Cited by 45 publications

(25 citation statements)

References 31 publications

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“…DOS calculations show that the conduction band of XNiSn compounds is dominated by the d-electrons of the X element. 36,42 Here, similarly to V doping in (Zr 0.25 Hf 0.75 )NiSn, 24 Ta substitution on the X site does not only increase the charge carrier concentration but also changes the DOS.…”

Section: à3mentioning

confidence: 90%

Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution

Gałązka

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Xie

et al. 2014

Journal of Applied Physics

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Articles you may be interested inThe thermoelectric performance of Ta substituted (ZrHf)NiSn-based half-Heusler compounds is studied. Here, Ta is used on the Hf site for controlling the charge carrier concentration in contrast to the widely used Sb substitution on the Sn site. The influence of the Ta content on the thermoelectric and transport properties of (Zr 0.3 Hf 0.7-x Ta x )NiSn (x ¼ 0, 0.01, 0.05) is investigated by means of Seebeck coefficient, electrical resistivity, thermal conductivity, and Hall coefficient measurements. The results are analyzed in context of the single parabolic band model. Ta substitution increases the charge carrier concentration and suppresses the influence of impurity band, which is present in the pristine (Zr 0.3 Hf 0.7 )NiSn. Moreover, Ta substitution decouples and simultaneously increases the density-of-states effective mass (m*) and the charge carrier mobility (l), leading to a larger weighted mobility lÁ(m*) 3/2 . The lattice thermal conductivity is slightly suppressed due to increased point defect scattering. As a result, a Figure

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Section: à3mentioning

confidence: 90%

Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution

Gałązka

Populoh

Xie

et al. 2014

Journal of Applied Physics

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“…Predicted TE factors of CoVSn compound, κ = 4.1 W/mK, S = 175 µV K −1 , zT = 0.53 at 900 K. [35] In 1995, Ögüt et al [36] predicted CoVSn with a MgAgAs (C1b) crystal structure as an intermetallic semiconductor using density functional theory (DFT) band structure calculations. Another study [37] applied the full-potential linear muffin-tin orbital (FP-LMTO) method to evaluate the electronic properties of CoVSn alloy and showed an indirect energy bandgap of 0.75 eV. Shi et al [38] calculated the electronic structure using the modified Becke-Johnson (MBJ) potential.…”

Section: Figure-1mentioning

confidence: 99%

Experimental Realization of Heavily p-doped Half-Heusler CoVSn Compound

et al. 2020

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Hypothetical half-Heusler (HH) ternary alloy of CoVSn has already been computationally investigated for possible spintronics and thermoelectric applications. We report the experimental realization of this compound and the characterizations of its thermoelectric properties. The material was synthesized by a solid-state reaction of the stoichiometric amounts of the elements via powder metallurgy (30 h mechanical milling and annealing at 900 °C for 20 h) and spark plasma sintering (SPS). The temperature-dependent ternary thermodynamic phase diagram of Co-V-Sn was further calculated. The phase diagram and detailed analysis of the synthesized material revealed the formation of the non-stoichiometry HH CoVSn, mixed with the binary intermetallic phases of SnV3, Co2Sn, and Co3V. The combination of X-ray diffraction, energy-dispersive X-ray spectroscopy, and thermoelectric transport properties confirmed the formation of a multi-phase compound. The analysis revealed the predicted thermoelectric features (zT = 0.53) of the highly doped CoVSn to be compromised by the formation of intermetallic phases (zT ≈ 0.007) during synthesis. The additional phases changed the properties from p- to overall n-type thermoelectric characteristics.

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“…The very small values of R for diamond provide a natural explanation for why polycrystalline diamond is such a good heat conductor. We have not included the thermoelectric half-Heusler compounds due to a paucity of data and a great variability [38][39][40][41][42] in anisotropy in the few data that do exist. For Bi 2 Te 3 the lattice thermal conductivity given is the planar value; the c-axis value is roughly half this.…”

Section: Sound Speed Anisotropy and Nanostructuring Effectivenesmentioning

confidence: 99%

Acoustic impedance and interface phonon scattering in Bi2Te3and other semiconducting materials

2013

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We present first principles calculations of the phonon dispersions of Bi 2 Te 3 , along with calculations of the sound speed anisotropy for a number of materials, and discuss these in relation to the acoustic phonon interface scattering in ceramics. The Bi 2 Te 3 phonon dispersions show agreement with what is known from neutron scattering for the optic modes, while we find a difference between the generalized gradient approximation and local density results for the acoustic branches. This is a consequence of an artificial compression of the van der Waals bonded gaps in the Bi 2 Te 3 structure when using the generalized gradient approximation. As a result local density approximation calculations provide a better description of the phonon dispersions in Bi 2 Te 3 . A key characteristic of the acoustic dispersions in several materials studied is the existence of a strong anisotropy in the velocities. Such an anisotropy may be a significant consideration in the reduction of lattice thermal conductivity by nanograin boundary scattering. This is a well-known technique commonly employed to improve thermoelectric performance. We develop a model to quantify the effect of this anisotropy for this interface scattering in ceramics and apply this to Bi 2 Te 3 and compare with PbTe and several other semiconductors.2

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Theoretical investigations of NiTiSn and CoVSn compounds

Cited by 45 publications

References 31 publications

Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution

Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution

Experimental Realization of Heavily p-doped Half-Heusler CoVSn Compound

Acoustic impedance and interface phonon scattering in Bi2Te3and other semiconducting materials

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Theoretical investigations of NiTiSn and CoVSn compounds

Cited by 45 publications

References 31 publications

Improved thermoelectric performance of (Zr0.3Hf0.7)NiSn half-Heusler compounds by Ta substitution

Improved thermoelectric performance of (Zr0.3Hf0.7)NiSn half-Heusler compounds by Ta substitution

Experimental Realization of Heavily p-doped Half-Heusler CoVSn Compound

Acoustic impedance and interface phonon scattering in Bi2Te3and other semiconducting materials

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Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution

Improved thermoelectric performance of (Zr_0.3Hf_0.7)NiSn half-Heusler compounds by Ta substitution