Enhanced thermoelectric power factor of half-Heusler solid solution Sc1-xTmxNiSb prepared by high-pressure high-temperature sintering method

Wolańska, Izabela; Synoradzki, K.; Ciesielski, Kamil; Załęski, Karol; Skokowski, P.; Kaczorowski, D.

doi:10.1016/j.matchemphys.2019.01.056

Cited by 27 publications

(27 citation statements)

References 45 publications

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“…With increasing temperature, ZT increased, reaching the maximum ZT = 0.10 at 810 K. This value is smaller than ZT reported for well-established p -type thermoelectrics [60], however it is similar to those found for other RE-based HH phases [1,3,51]. At room temperature ZT = 0.01, which is almost two times smaller than the value reported before for an arc-melted sample [31], yet four times larger when compared with ZT of our sample, prepared by high-pressure high-temperature (HPHT) sintering [42]. The main reason for the reduced ZT values is very low electrical conductivity, opening a way for enhancing the thermoelectric figure of merit by appropriate substitutions.…”

Section: Resultssupporting

confidence: 85%

“…The temperature dependence of the power factor (PF = S 2 / ρ ) calculated from the measured data of ScNiSb is presented in Figure 3c. On increasing temperature, PF starts growing above about 50 K and reaches a maximum of 0.90(4) × 10 −3 W m K 2 at 810 K. This value is similar to those determined for other RE-based HH phases [3,5,38,39,40,41,42] and other thermoelectric materials [49].…”

Section: Resultssupporting

confidence: 84%

“…Motivated by the literature data, we decided to investigate high-temperature thermoelectric properties of ScNiSb, which seemed to be not explored before, and low-temperature thermoelectric properties in order to not only compare our results with those already published, but also to search for other physical properties, e.g., superconductivity. This research is a part of our comprehensive studies on thermoelectricity in RE-based HH phases [38,39,40,41,42].…”

Section: Introductionmentioning

confidence: 99%

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Thermal and Electronic Transport Properties of the Half-Heusler Phase ScNiSb

et al. 2019

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Thermoelectric properties of the half-Heusler phase ScNiSb (space group F 4 ¯ 3m) were studied on a polycrystalline single-phase sample obtained by arc-melting and spark-plasma-sintering techniques. Measurements of the thermopower, electrical resistivity, and thermal conductivity were performed in the wide temperature range 2–950 K. The material appeared as a p-type conductor, with a fairly large, positive Seebeck coefficient of about 240 μV K−1 near 450 K. Nevertheless, the measured electrical resistivity values were relatively high (83 μΩm at 350 K), resulting in a rather small magnitude of the power factor (less than 1 × 10−3 W m−1 K−2) in the temperature range examined. Furthermore, the thermal conductivity was high, with a local minimum of about 6 W m−1 K−1 occurring near 600 K. As a result, the dimensionless thermoelectric figure of merit showed a maximum of 0.1 at 810 K. This work suggests that ScNiSb could be a promising base compound for obtaining thermoelectric materials for energy conversion at high temperatures.

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Section: Resultssupporting

confidence: 85%

Section: Resultssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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Thermal and Electronic Transport Properties of the Half-Heusler Phase ScNiSb

et al. 2019

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“…In this case, the energy states of impurity donor 2 and acceptor А 1 bands (donor-acceptor pairs) appear in the band gap of the semiconductor Er1-xZrxNiSb, which determine its conduction mechanisms. The study of Tm1-xScxNiSb solid solution showed that the substitution of rare earth Tm atoms by Sc atoms does not change the type of majority current carriers and the holes remain the main carriers of electricity [9].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and electrical transport properties of Er1-xScxNiSb semiconducting solid solution

Romaka

Stadnyk

Ромака

et al. 2021

Phys. Chem. Solid St.

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Samples of Er1-xScxNiSb (x = 0–0.10) solid solution were synthesized by an arc-melting and the effect of doping by Sc atoms on the electrokinetic and energetic characteristics of the half-Heusler ErNiSb phase was investigated. It was established that at the studied concentrations the main carriers of electricity in the Er1-xScxNiSb semiconductor are holes. It was shown that doping of p-ErNiSb compound by Sc atoms introduced by substitution of Er atoms in 4a position is accompanied by the occupation of presented vacancies in position 4a, which leads to the reduction and elimination of structural defects of acceptor nature and corresponding acceptor band. The concentration ratio of ionized acceptors and donors generated in Er1-xScxNiSb determines the position of the Fermi level and the mechanisms of electrical conduction. The investigated solid solution Er1-xScxNiSb is a promising thermoelectric material.

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“…The study of a solid solution of Tm 1-x Sc x NiSb in the concentration range ( x = 0-1) showed that the substitution of Tm atoms for Sc does not change the type of the main current carriers and the holes remain the main carriers of electricity [2]. Below we return to the analysis of the results of this work.…”

Section: Introductionmentioning

confidence: 91%

RESEARCH OF THERMOMETRIC MATERIAL Er1-xScxNiSb. I. MODELLING OF PERFORMANCES

Krayovskyy¹,

Pashkevych²,

Horpenuk³

et al. 2021

MEM

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Automated The results of modeling performances of the semiconductor solid solution Er1-xScxNiSb are presented, which can be a promising thermometric material for the manufacture of sensitive elements of thermoelectric and electroresistive thermocouples. Fullprof Suite software was used to model the crystallographic characteristics of the Er1-xScxNiSb thermometric material. Modeling of the electronic structure of Er1-xScxNiSb was performed by Coring-Kon-Rostocker methods in the approximation of coherent potential and local density using the exchange-correlation potential Moruzzi-Janak-Williams and Linear Muffin-Tin Orbital in the framework of DFT density functional theory. The Brillouin zone was divided into 1000 k-points, which were used to model energetic performances by calculating DOS. The width of the energy window was 22 eV and was chosen to capture all semi-core states of p-elements. Full potential (FP) was used in the representation of the linear MT orbital in the representation of plane waves. The accuracy of calculating the position of the Fermi level was εF ± 6 meV. To verify the existence of a continuous solid solution, Er1-xScxNiSb substitution, the change in the values of the period of the unit cell a (x) was calculated within the framework of the DFT density functional theory in the range x = 0–1.0. It is presented that the calculated and experimentally obtained dependences of the period of the unit cell a(x) Er1-xScxNiSb are almost parallel, which confirms the correctness of the used tools and the obtained modeling results. To research the possibility of obtaining thermometric material Er1-xScxNiSb in the form of a continuous solid solution was performed modeling of thermodynamic calculations in the approximation of harmonic oscillations of atoms in the theory of DFT density functional for a hypothetical solid solution Er1-xScxNiSb, x = 0–1.0. It is shown that the change in the values of free energy ΔG(x) (Helmholtz potential) passes through the minimum at the concentration x≈0.1 for all temperatures of possible homogenizing annealing of the samples, indicating the solubility limit of Sc atoms in the structure of the ErNiSb compound. The presence of this minimum indicates that the substitution of Er atoms for Sc atoms in the ErNiSb compound is energetically advantageous only up to the concentration of impurity atoms Sc, x≈0.1. At higher concentrations of Sc atoms, x> 0.10, stratification occurs (spinoidal phase decay). It is shown that modeling of the mixing entropy behavior S even at a hypothetical temperature T = 4000 K shows the absence of complete solubility of Sc atoms in Er1-xScxNiSb. To model the energetic and kinetic performances of the semiconductor thermometric material Er1-xScxNiSb, particularly the behavior of the Fermi level F e , bandgap width g e the distribution of the density of electronic states (DOS) and the behavior of its electrical resistance ρ(x, T) is calculated for an ordered variant of the structure in which the Er atoms in position 4a are replaced by Sc atoms. It is shown that the ErNiSb compound is a semiconductor of the electronic conductivity type, in which the Fermi level is located near the level of the conduction band C e . The modeling showed that at higher concentrations of Sc atoms, the number of generated acceptors exceeds the concentration of uncontrolled donors, and the concentration of free holes exceeds the concentration of electrons. Under these conditions, the Fermi level F e approaches, and then the level of the valence band Er1- xScxNiSb crosses: the dielectric-metal conductivity transition occurs. The experiment should change the sign of the thermo-emf coefficient α(x, T) Er1-xScxNiSb from negative to positive, and the intersection of the Fermi level F e and the valence band changes the conductivity from activating to metallic: on the dependences ln(ρ(1/T)) the activation sites disappear, and the values of resistivity ρ increase with temperature.

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Enhanced thermoelectric power factor of half-Heusler solid solution Sc1-xTmxNiSb prepared by high-pressure high-temperature sintering method

Cited by 27 publications

References 45 publications

Thermal and Electronic Transport Properties of the Half-Heusler Phase ScNiSb

Thermal and Electronic Transport Properties of the Half-Heusler Phase ScNiSb

Synthesis and electrical transport properties of Er1-xScxNiSb semiconducting solid solution

RESEARCH OF THERMOMETRIC MATERIAL Er1-xScxNiSb. I. MODELLING OF PERFORMANCES

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