Intrinsic point defects in half-Heusler AuMnSn

Chibueze, Timothy C.; Raji, A.T.; Okoye, C.M.I.

doi:10.1016/j.jpcs.2019.109328

Cited by 12 publications

(4 citation statements)

References 55 publications

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“…It has been speculated that slight change in alloy composition in the experimental samples due to point defects may explain this deviation from the usual trend observed in semiconductors [57,64,65]. While external doping is the commonly employed point defect engineering strategy for tailoring carrier concentration and mobility [44][45][46][88][89][90][91][92][93][94], intrinsic point defects can also modify electronic structure, carrier concentration, and hence transport properties of half-Heusler alloys [95][96][97][98][99][100][101][102]. The high-resolution angle-resolved photoemission spectroscopy (ARPES) measurements can be used to gain insights into the defect-induced changes in the electronic structure [99,103].…”

Section: B Electronic Band Structure and Density Of Statesmentioning

confidence: 99%

Decisive role of interstitial defects in half-Heusler semiconductors: An ab initio study

Dey

Dutta

2021

Phys. Rev. Materials

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Half-Heusler semiconductors satisfying 18-electron rule typically display promising characteristics for thermoelectric applications. A persistent inconsistency between the type of charge carriers in some of these alloys as obtained from experiment and theory however casts serious doubt on the computational prediction of new and efficient half-Heusler alloys. To gain insights into the origin of this disparity, we have investigated the effect of intrinsic point defects on the electronic structure of four frequently studied half-Heusler alloys of the form XY Z with Y being Ni or Co. Using state-of-the-art ab initio calculations, our study reveals that interstitial Ni and Co are energetically most stable point defects in these alloys. Remarkably, interstitial defect modifies the location of the Fermi level inside the band gap as well as the value of the band gap, thereby bringing in close agreement with the corresponding experimental result. This work thus highlights the decisive role played by interstitial defects in thermoelectric half-Heusler alloys, which may open a new avenue for deliberately utilizing these defects as a strategy for tailoring electronic structure and hence the corresponding thermoelectric properties.

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Section: B Electronic Band Structure and Density Of Statesmentioning

confidence: 99%

Decisive role of interstitial defects in half-Heusler semiconductors: An ab initio study

Dey

Dutta

2021

Phys. Rev. Materials

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“…So we use the VASP to calculate the total energies of competing phases to determine the region of phase stability. Then we consider three types of intrinsic defects (vacancy, interstitial, and antisite defects) [44][45][46][47][48] in a supercell containing 96 atoms and compute the formation energies under the different conditions of the accessible region.…”

Section: Defect Formation Energy Calculationmentioning

confidence: 99%

Study of thermoelectric performance and intrinsic defect of promising n-type half-Heusler FeGeW

Xu¹,

Sun²,

Jian³

et al. 2022

J. Phys. D: Appl. Phys.

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Half-Heusler compounds are considered promising thermoelectric materials for high-temperature power generation due to their good electrical properties and thermal stability. Some new half-Heuslers with excellent thermoelectric properties are found to be p-type, the discovery of competitive n-type half-Heusler materials has been extremely challenging. Here, we report a new half-Heusler compound FeGeW through first-principles calculation, which exhibits a high ZT of 2.36 at 1000 K. Systematically studied its thermoelectric performance indicates that a large dispersion or small band effective mass of conduction band can efficiently improve the electrical conductivity of n-type FeGeW. From the calculated formation energy of intrinsic point defects, we find that positive charged Fe interstitial are found to be the dominant defect at Fe-rich/Ge-poor condition, which account for the n-type conduction. Moreover the transition levels of Fe interstitial defect is shallow, which means that this donor defect does not damage electrical conductivity and thermoelectric performance. These results not only find a new n-type half-Heusler compound FeGeW, but also are helpful for understanding the roles of point defects in FeGeW, which is expected to encourage more experimental and theoretical investigations to study this kind of n-type half-Heusler thermoelectric material and seek out strategies to optimize thermoelectric performance using intrinsic point defect.

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“…For that reason, many researchers have recently spent many efforts in searching for enhanced HH thermoelectric materials. That enhancement can be attained through reducing the lattice thermal conductivity via optimizing nanoparticle phonon scattering centers [28], point defects [29], and grain size reduction [30].…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties Investigation of Ni/Co Doped ZrCoBi Half-Heusler Alloy

Al-Elaimi

2023

East Eur. J. Phys.

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Half-Heusler (HH) thermoelectric (TE) composites have been extensively inspected due to their excellent TE properties in the medium- to high-temperature range. First-principle calculations make it easier to discover or improve more HH compounds. This article presents an ab initio theoretical evaluation of TE properties of Half-Heusler alloy, when doped with Nickel (Ni), using FP-LAPW and the semi classic Boltzmann theory. Thermoelectric parameters were calculated using BoltzTraP code, like Seebeck coefficient ( ), electrical conductivity to relaxation time ratio ( ), electronic thermal conductivity to relaxation time ratio ( ), thermoelectric power factor to relaxation time ratio ( ), and the dimensionless figure-of-merit ( ) in a temperature range of . Calculated Seebeck coefficient reveals that the studied alloys show a tendency to conduct as p-type with balanced TE performance between both charge carriers (holes and electrons). A high electronic thermal conductivity value is found, which predicts a potential use in heat sink applications for the investigated alloys. Obtained results, such as a high thermoelectric power factor and , postulate that alloys could have potential thermoelectric applications.

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Intrinsic point defects in half-Heusler AuMnSn

Cited by 12 publications

References 55 publications

Decisive role of interstitial defects in half-Heusler semiconductors: An ab initio study

Decisive role of interstitial defects in half-Heusler semiconductors: An ab initio study

Study of thermoelectric performance and intrinsic defect of promising n-type half-Heusler FeGeW

Thermoelectric Properties Investigation of Ni/Co Doped ZrCoBi Half-Heusler Alloy

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