Analysis of structural and electronic properties of NiTiZ (Z = Si, Ge, Sn and Sb) under high-pressure using ab initio calculations

Pereira, Aercio F.F. de F.; Souza, Sérgio Michielon de; Ghosh, Angsula

doi:10.1016/j.mtcomm.2020.101613

Cited by 4 publications

(3 citation statements)

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“…[ 9 ] This is performed using PHONO3PY, which is incorporated into Quantum Espresso. [ 35,36 ] To obtain atomic forces, the total energies were minimized until the energy convergences became less than 1 × 10 −9 eV. For the TC calculation, 2 × 2 × 2 supercell is used for bulk copper, while a 2 × 2 × 1 supercell is selected for the Cu(111) surface and the Cu(111)/Gr heterosystem, respectively.…”

Section: Computational Methodologymentioning

confidence: 99%

Thermal and Electrical Conductivity of Copper‐Graphene Heterosystem: An Effect of Strain and Thickness

et al. 2023

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Copper‐graphene (Cu/Gr) composite carries high thermal (κ) and electrical (σ) conductivities compared with pristine copper film/surface. For further improvement, strain is applied (compressive and tensile) and thickness is changed (of both copper and graphene). It is observed that electronic thermal conductivity (κe) and σ enhance from 320.72 to 869.765 W mK−1 and 5.28 × 107 to 23.01 × 107 S m−1, respectively, by applying 0.20% compressive strain. With the increase in copper thickness (three to seven layers) in Cu(111)/single‐layer‐graphene (SLG) heterosystem, κe increases from 320.72 to 571.81 W mK−1 while electrical resistivity (ρ ∝ (1/σ)) decreases from 0.189 × 10−7 to 0.117 × 10−7 Ωm. Furthermore, with the increase in graphene thickness (one to four layers) in seven‐layer Cu(111)/multilayer‐graphene (MLG) heterosystem, κe enhances upto 126% while ρ decreases upto 70% compared with the three‐layer Cu(111)/SLG. A large available state near Fermi level (of Cu/Gr heterosystem) offers the conduction of more electrons from valence to conduction bands. The increasing thickness broadens this state and enhances conduction electrons. The electron localization function decreases with increasing thickness, suggesting electrons are delocalized at copper‐graphene junction, resulting in an increase of free electrons that enhance κe and σ. Herein, it is useful in advancing the thermal management of electronic chips and in applying hybrid copper‐graphene interconnects.

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Section: Computational Methodologymentioning

confidence: 99%

Thermal and Electrical Conductivity of Copper‐Graphene Heterosystem: An Effect of Strain and Thickness

et al. 2023

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“…TiNi 2 Sn, Ni 3 Sn 4 , Ti 6 Sn 5 , Sn) increases the charge carrier concentration in the sample, raising the electrical conductivity and lowering the absolute value of the Seebeck coefficient [25,26,[29][30][31][32]. On the other hand, point defects act as intrinsic dopants and their role on the electronic and thermoelectric properties was investigated both experimentally [12,27,28], and theoretically [12,[15][16][17][18][19]33] by several authors, without achieving shared and unambiguous results. It was demonstrated that a small excess of Ni leads to the partial occupancy of the vacant sites (interstitial Ni defect) expanding the cell, without precipitation of the Heusler compound TiNi 2 Sn due to the slight solubility of Ni in TiNiSn [21,28,34].…”

Section: Introductionmentioning

confidence: 99%

Experimental and computational study of the role of defects and secondary phases on the thermoelectric properties of TiNi_1+xSn (0 ≤ x ≤ 0.12) half Heusler compounds

Ascrizzi¹,

Casassa²,

Daga³

et al. 2023

Nanotechnology

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The half Heusler TiNiSn compound is a model system for understanding the relationship among structural, electronic, microstructural and thermoelectric properties. However, the role of defects that deviate from the ideal crystal structure is far from being fully described.In this work, TiNi1+xSn alloys (x = 0, 0.03, 0.06, 0.12) were synthesized by arc melting elemental metals and annealed to achieve equilibrium conditions. Experimental values of the Seebeck coefficient and electrical resistivity, obtained from this work and from the literature, scale with the measured carrier concentration, due to different amounts of secondary phases and interstitial nickel. Density functional theory calculations showed that the presence of both interstitial Ni defects and composition conserving defects narrows the band gap with respect to the defect free structure, affecting the transport properties. Accordingly, results of experimental investigations have been explained confirming that interstitial Ni defects, as well as secondary phases, promote a metallic behaviour, raising the electrical conductivity and lowering the absolute values of the Seebeck coefficient.

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“…The nickel element is of low-cost and earth-abundant, which is economic to realize large-scale industrial applications in TE matrices. Two works , have predicted the TE properties of NiTiZ (Z = Si, Ge, and Sn) by treating the carrier relaxation time as a constant. However, the validity of TE properties based on the constant carrier relaxation time approximation is questionable .…”

Section: Introductionmentioning

confidence: 99%

Computational Search for Better Thermoelectric Performance in Nickel-Based Half-Heusler Compounds

et al. 2021

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Half-Heusler alloys have recently received extensive attention because of their promising thermoelectric (TE) properties and great potential for applications requiring efficient thermoelectricity. Although the conversion efficiency of these materials can be greatly improved by doping, it is still far away from the real-life applications. Therefore, search for better parent TE compounds is deemed urgent. Using a highthroughput search method based on first-principles calculations in newly proposed 378 half-Heusler alloys, we identify nine nickel-based half-Heusler semiconductors as candidates and systematically study their mechanical, electronic, and transport properties. Their mechanical and dynamical stabilities are verified based on the calculated elastic constants and phonon spectra. The electronic structure calculations indicate the existence of direct energy gaps in the NiVZ (Z = Al, Ga, and In) and indirect energy gaps in the NiTiZ (Z = Si, Ge, and Sn) and NiScZ (Z = P, As, and Sb) compounds. Among them, NiVAl, NiVGa, and NiVIn exhibit a sharp slope of density of states near the Fermi level, which is predicted to be essential for a high TE performance. Further investigation on carrier concentration and temperature dependence of TE properties shows the high power factors of NiVAl, NiVGa, and NiVIn, which are responsible for their high figure of merit values. The highest maximum power factor of 5.152 mW m −1 K −2 and figure of merit of 0.309 are predicted for pristine half-Heusler NiVIn, which are larger than the values of some known pristine and doped half-Heusler TE materials. Our work opens up new avenues for rationally searching better TE materials among half-Heusler alloys for applications in fields requiring efficient thermoelectricity.

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Analysis of structural and electronic properties of NiTiZ (Z = Si, Ge, Sn and Sb) under high-pressure using ab initio calculations

Cited by 4 publications

References 70 publications

Thermal and Electrical Conductivity of Copper‐Graphene Heterosystem: An Effect of Strain and Thickness

Thermal and Electrical Conductivity of Copper‐Graphene Heterosystem: An Effect of Strain and Thickness

Experimental and computational study of the role of defects and secondary phases on the thermoelectric properties of TiNi_1+xSn (0 ≤ x ≤ 0.12) half Heusler compounds

Computational Search for Better Thermoelectric Performance in Nickel-Based Half-Heusler Compounds

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Analysis of structural and electronic properties of NiTiZ (Z = Si, Ge, Sn and Sb) under high-pressure using ab initio calculations

Cited by 4 publications

References 70 publications

Thermal and Electrical Conductivity of Copper‐Graphene Heterosystem: An Effect of Strain and Thickness

Thermal and Electrical Conductivity of Copper‐Graphene Heterosystem: An Effect of Strain and Thickness

Experimental and computational study of the role of defects and secondary phases on the thermoelectric properties of TiNi1+xSn (0 ≤ x ≤ 0.12) half Heusler compounds

Computational Search for Better Thermoelectric Performance in Nickel-Based Half-Heusler Compounds

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Analysis of structural and electronic properties of NiTiZ (Z = Si, Ge, Sn and Sb) under high-pressure using ab initio calculations

Experimental and computational study of the role of defects and secondary phases on the thermoelectric properties of TiNi_1+xSn (0 ≤ x ≤ 0.12) half Heusler compounds