Investigation of high figure of merit in semiconductor XHfGe (X = Ni and Pd) half-Heusler alloys: Ab-initio study

Bendahma, F.; Mana, M.; Terkhi, S.; Cherid, S.; Bestani, Benaouda; Bentata, S.

doi:10.1016/j.cocom.2019.e00407

Cited by 17 publications

(10 citation statements)

References 38 publications

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“…The lattice constant of PdTiPb was found to be higher than that of PdTiGe which is due to the bigger electronic shell of the Pb atom. The optimized lattice constants are consistent with the analogous materials like PdTiSn (6.230 Å), PdZrGe (6.159 Å), PdHfSn (6.35 Å) and PdHfGe (6.15 Å) [8][9][10]21].…”

Section: Computational and Structural Detailssupporting

confidence: 80%

“…The values B and Y predict that PdTiGe is harder and stiffer than PdTiPb which is possibly due to the p electronic states of Ge atom which experiences a strong coulombic attraction than that of p electronic state of Pb atom. Moreover, computed values of B and Y predict that the sample compounds are comparatively softer and less stiff than analogous compounds like NbPdSi, NbPtSi [23], and PdHfGe [21]. The value of

θ_{D}

predicts the strong binding force among the constituent atoms in PdTiGe consistent to B .…”

Section: Resultsmentioning

confidence: 99%

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DFT study of structural, mechanical, thermodynamic, electronic, and thermoelectric properties of new PdTiZ (Z = Ge and Pb) half Heusler compounds

Kalita

Limbu

Ram

et al. 2022

Int J of Quantum Chemistry

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A first principle investigation of structural, mechanical, thermodynamical, electronic, and thermoelectric properties of PdTiZ (Z = Ge and Pb) were carried out using the plane‐wave pseudopotential (PP‐PW) method. The exchange‐correlation between the electrons was considered with the generalized gradient approximation of Perdew‐Burke‐Ernzerhof (PBE‐GGA). The energy band structure of the sample materials shows that it is a semiconductor with indirect energy band gaps of 0.66 eV and 0.387 eV in PdTiGe and PdTiPb, respectively, with the density of states being mainly dominated by the p states of Z and d states of Ti atom in the vicinity of the Fermi energy level. The sample compounds were found to be mechanically and dynamically stable in their non‐magnetic cubic phase. PdTiGe was found to be harder and stiffer than PdTiPb. The thermodynamic study revealed that pressure has a negative effect on heat capacity, whereas Debye temperature increases with enhanced pressure in both the sample compounds. The thermoelectric properties of the sample compounds predicted that p‐type nature of the sample compounds possess better thermoelectric performance. The room temperature Seebeck coefficient (S) values were found to be 98.73 μV/K and 94.82 μV/K for PdTiGe and PdTiPb, respectively, whereas S values of 245.73 μV/K and 218.77 μV/K at 1200 K at n = 1021 cm−3. The lowest values of lattice thermal conductivity (KL) of 2.28 W/m‐K and .98 W/m‐K were observed for PdTiGe and PdTiPb, respectively. The optimum dimensionless figure of merits of .66 (1200 K) and .64 (1000 K) were found for p‐type PdTiGe and PdTiPb, respectively, at optimum carrier concentration.

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Section: Computational and Structural Detailssupporting

confidence: 80%

θ_{D}

predicts the strong binding force among the constituent atoms in PdTiGe consistent to B .…”

Section: Resultsmentioning

confidence: 99%

DFT study of structural, mechanical, thermodynamic, electronic, and thermoelectric properties of new PdTiZ (Z = Ge and Pb) half Heusler compounds

Kalita

Limbu

Ram

et al. 2022

Int J of Quantum Chemistry

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“…2 shows the maximum ZT achieved for bulk thermoelectric materials over the past six years as a function of temperature. 33–234…”

Section: Strategiesmentioning

confidence: 99%

Recent advances in designing thermoelectric materials

2022

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“…That is, the lattice constant increases with the atomic size of the Z element in CsCaZ compounds. However, the B value decreases in the following sequence: B (CsCaGe) > B (CsCaSn) > B (CsCaPb), conversely to (a) and the unit cell volume (V ), which follow the relationship (B V −1 ) [44].…”

Section: Structural Stabilitymentioning

confidence: 99%

Half-metallic and thermodynamic properties of new d 0 CsCaZ (Z= Ge, Sn and Pb) half Heusler alloys: A spin-based devices vision for the future

et al. 2022

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Density functional theory (DFT) was applied to investigate the structural, electronic, elastic, magnetic, thermodynamic and half-metallic properties of the newly d0 Heusler alloys (HAs) CsCaZ (Z= Ge, Sn and Pb). Spin-polarised calculations show that the compounds studied are half-metallic with a magnetic moment of 1.00 μB at the equilibrium lattice parameter, which obeys the well-known Slater–Pauling rule Mtot = 8 – Zt. The half-metallic behavior of the compounds CsCaGe, CsCaSn and CsCaPb is predicted with respect to the equilibrium lattice constants for CsCaGe, CsCaSn and CsCaPb with a narrow band gap in the majority spin channel. Furthermore, the elastic constants (Cij) showed that these materials are ductile and anisotropic. In addition, the negative values of the calculated formation energy and cohesion energy indicate that CsCaZ (Z= Ge, Sn and Pb) are likely to be experimentally synthesized. Non-equilibrium Gibbs function is employed to calculate the thermodynamic properties through the quasi-harmonic Debye model in which the bulk modulus, heat capacity, Debye temperature, thermal expansion coefficient, and entropy are investigated at 0-20 Gpa pressure and 0-1200 K temperature ranges. The significant half-metallic behavior makes the CsCaZ (Z= Ge, Sn and Pb) compounds strong candidates for spintronic applications.

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Investigation of high figure of merit in semiconductor XHfGe (X = Ni and Pd) half-Heusler alloys: Ab-initio study

Cited by 17 publications

References 38 publications

DFT study of structural, mechanical, thermodynamic, electronic, and thermoelectric properties of new PdTiZ (Z = Ge and Pb) half Heusler compounds

DFT study of structural, mechanical, thermodynamic, electronic, and thermoelectric properties of new PdTiZ (Z = Ge and Pb) half Heusler compounds

Recent advances in designing thermoelectric materials

Half-metallic and thermodynamic properties of new d 0 CsCaZ (Z= Ge, Sn and Pb) half Heusler alloys: A spin-based devices vision for the future

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