Electronic transport in Heusler-type<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Fe</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mtext>VAl</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>M</mml:mi><mml:mi>x</mml:mi></mml:msub></mml:mrow></mml:math>alloys<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml

Vasundhara, М.; Srinivas, V.; Rao, Vishal Govind

doi:10.1103/physrevb.77.224415

Cited by 76 publications

(43 citation statements)

References 26 publications

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“…5(a) is around 5x10 18 (Ωms) −1 for x = 0.0. The experimental resistivity, ρ ∼ 0.75 mΩcm (300 K) 56 yields a τ value of ∼2.10 × 10 −14 s, being higher than the 0.90 × 10 −14 s (GGA) and 1.4 × 10 −14 s (B1WC). 19 While using a τ value of 2.10 × 10 −14 s and (σ/τ) as 5 × 10 18 (Ωms) −1 , the calculated resistivity of Fe 2 VAl is 0.95 (mΩcm) at 300 K, which is in close agreement with the experimental one.…”

Section: B Optical and Transport Propertiesmentioning

confidence: 99%

“…19 While using a τ value of 2.10 × 10 −14 s and (σ/τ) as 5 × 10 18 (Ωms) −1 , the calculated resistivity of Fe 2 VAl is 0.95 (mΩcm) at 300 K, which is in close agreement with the experimental one. 56 The calculated charge concentration in Fe 2 VAl is 3.05 × 10 20 cm 3 , is consistent with the experimental value of 3.7 × 10 20 cm 3 22 but smaller than the 4.8 × 10 20 cm 3 obtained from a Hall effect study at 300 K. 55 Since τ is generally difficult to systematically compute and for x=0.25, 0.50, 0.75, and 1.00 are yet unknown at least from experiment, we cannot unambiguously determined the resistivity. However, from Fig.…”

Section: B Optical and Transport Propertiesmentioning

confidence: 99%

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Electronic, optical, and thermoelectric properties of Fe2+xV1−xAl

P.¹,

Sandeep

Shankar

et al. 2017

AIP Advances

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We report the electronic, optical, and thermoelectric properties of full-Heusler alloy Fe2VAl with Fe antisite doping (Fe2+xV1−xAl) as obtained from the first-principles Tran-Blaha modified Becke-Johnson potential. The results are discussed in relation to the available experimental data and show good agreements for the band gap, magnetic moment, and optical spectra. Exploring our transport data for thermoelectric applicability suggest that Fe2+xV1−xAl is a good candidate with a high figure of merit (ZT) 0.75(0.65) for x = 0.25(0.50) at room temperature.

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Section: B Optical and Transport Propertiesmentioning

confidence: 99%

Section: B Optical and Transport Propertiesmentioning

confidence: 99%

Electronic, optical, and thermoelectric properties of Fe2+xV1−xAl

P.¹,

Sandeep

Shankar

et al. 2017

AIP Advances

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“…Recently, the electronic properties of Fe 2 VAl 1Àx M x (M: B, In, Si) alloys have been systematically investigated by Vasundhara et al 10) As pointed out by Mahan and Sofo, 11) a narrow peak in the density of states (DOS) at a few k B T from the Fermi level can be beneficial for improving the thermoelectric performance. The above mentioned materials, indeed, possess relatively large Seebeck coefficients and high power factors S 2 .…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al<SUB>2</SUB>Ru and Ga<SUB>2</SUB>Ru Synthesized by Spark Plasma Sintering Process

et al. 2010

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The authors report the electrical and thermal transport properties of binary semiconducting intermetallic Al 2 Ru and Ga 2 Ru compounds from 373 to 973 K. We synthesized sintered pellets of Al 2 Ru and Ga 2 Ru by the spark plasma sintering (SPS) method, resulted in a removal of small amount of a secondary phase and of cracks. The maximum Seebeck coefficient of Al 2 Ru and Ga 2 Ru shows a large positive value of 200 mV/K and 360 mV/K, respectively. In particular, a large power factor $2:8 mW/m-K 2 was obtained at 773 K in Ga 2 Ru compound. The dimensionless figures of merit ZT of sintered Al 2 Ru and Ga 2 Ru samples monotonically increase with increasing temperature and reach a maximum value of 0.20 and 0.45 at about 873 K and 773 K, respectively.

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“…In addition, several attempts have been made to increase the magnitude of S, for example by incorporating anti-site defects (increasing ratio of V/Fe) 11 or by doping at the Al site with Si, Ge, and Sn. [12][13][14] In the present work we will not be concerned with the V/Fe anti-site defects since they give rise to localized states near the Fermi energy and their effects on the transport properties are difficult to calculate accurately. Our focus here is to see how well one can understand the experimental data without involving the effect of defects.…”

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confidence: 99%

Effect of onsite Coulomb repulsion on thermoelectric properties of full-Heusler compounds with pseudogaps

Lee

Mahanti

2011

Phys. Rev. B

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Electronic structure calculations using local density and generalized gradient(LDA/GGA) approximations for the full Heusler compound Fe2VAl show that it is a pseudo-gap (negative gap) system with very small density of states (DOS) at the Fermi level but rapidly rising DOS away from it, a feature that makes this compound a promising thermoelectric material. Thermopower (S) measurements in nominally pure and n-doped Fe2VAl give indeed large values of S (∼-150 µV/K at 200 K). To improve on the inadequacy of LDA/GGA in handling d-electron systems and to understand the origin of large thermopowers measured, we have carried out electronic structure calculations using GGA+U method with several values of the on-site Coulomb interaction parameter U including the ones calculated using constrained density functional theory (DFT). For the latter, we found Fe2VAl to be a narrow band gap semiconductor with a gap of 0.55 eV. With the calculated band structures, we have studied the carrier concentration and temperature dependence of S using Boltzmann transport equation in constant relaxation time approximation for both the pseudo-gap and gapped cases.Comparison between theory and experiment suggests that neither the pseudo-gap nor the finite gap (0.55 eV) model can explain all the transport properties consistently. Therefore treatment of U beyond simple mean-field approach (done in GGA+U) and/or inclusion of defect induced changes in the host electronic structure might be important in understanding the experiments.

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Electronic transport in Heusler-typeFe2VAl1−xMxalloys

Cited by 76 publications

References 26 publications

Electronic, optical, and thermoelectric properties of Fe2+xV1−xAl

Electronic, optical, and thermoelectric properties of Fe2+xV1−xAl

Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al<SUB>2</SUB>Ru and Ga<SUB>2</SUB>Ru Synthesized by Spark Plasma Sintering Process

Effect of onsite Coulomb repulsion on thermoelectric properties of full-Heusler compounds with pseudogaps

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