High thermoelectric power factor in alloys based on CoSi

Skoug, Eric J.; Zhou, Chen; Pei, Yangli; Morelli, Donald T.

doi:10.1063/1.3072799

Cited by 46 publications

(38 citation statements)

References 15 publications

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“…Even though such a ZT value is still small compared to that of the optimized Bi 2 Te 3 (Rowe, 1995). The thermoelectric power factor ( S 2 /ρ) of SrSi 1.94 Ge 0.06 is estimated to be about 1.6 × 10 −3 W/m-K 2 (Table 2), comparable to the thermoelectric materials such as Bi 2 Te 3 , K 2 Bi 8 Se 13 , and CoSi 1 − x Ge x (Rowe, 1995; Chung et al, 1997; Skoug et al, 2009). Hence, it is obvious that the thermoelectric power factor of SrSi 2 can be effectively enhanced by band engineering through the introduction of negative chemical pressure in the SrSi 2 lattice with Ge substitution.…”

Section: Srsi2-based Alloysmentioning

confidence: 75%

Optimization of thermoelectric performance of SrSi2-based alloys via the modification in band structure and phonon-point-defect scattering

2014

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Thermoelectric properties of alkaline-earth-metal disilicides are strongly dependent on their electronic band structure in the vicinity of the Fermi level. In particular, the strontium disilicide, SrSi2 with a narrow band gap of about few tens of meV is composed of non-toxic, naturally abundant elements, and its thermoelectric properties are very sensitive to the substitution/alloying with third elements. In this article, we summarize the thermoelectric performance of substituted and Sr-deficient/Sr-rich SrSi2 alloys to realize the high thermoelectric figure-of-merit (ZT) for practical applications in the electronic and thermoelectric aspects, and also to explore the alternative routes to further improve its ZT value.

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Section: Srsi2-based Alloysmentioning

confidence: 75%

Optimization of thermoelectric performance of SrSi2-based alloys via the modification in band structure and phonon-point-defect scattering

2014

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“…Here, z = θ/T is the reciprocal reduced temperature, ϕ(z) = ln(1 -e -z ) -D(z)/3, d(z) is the standard tabulated Debye function, and θ is the Debye temperature expressed through molar volume V and bulk compression modulus B as (2) Here, , N A , and k B are the Planck, Avogadro, and Boltzmann constants, respectively; Ξ(σ) is the function dependent on Poisson ratio σ; and μ' is the molar mass that is responsible for the vibrating atom mass. Since the "effective" Debye modes are considered here, we follow [11] and use the average molar mass μ' = (μ Co + μ Si )/2 = 0.04351 kg/mol as the value of μ'.…”

Section: Description Of the Modelmentioning

confidence: 99%

“…Cobalt monosilicide CoSi is one of the most promising materials for creating thermogenerators, which is caused by the relatively high efficiency of CoSi-based thermogenerators and the physicochemical and mechanical properties of this compound (which are appropriate for technical applications) [1][2][3]. Nevertheless, many important thermal and elastic properties of CoSi are poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic simulation of the elastic and thermal properties of cobalt monosilicide

2016

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A self-consistent thermodynamic model is used to calculate the temperature dependences of the heat capacity, the thermal expansion coefficient, the bulk compression modulus, the density, Debye temperature, and the Grüneisen parameter of CoSi in the temperature range 0-1400 K. The calculation results agree well with the existing experimental data and can be used to predict the properties of CoSi in the temperature range that has not been experimentally studied. Cobalt monosilicide is shown to have a significant phonon anharmonicity, which can be caused by an electron-phonon interaction, and this anharmonicity should be taken into account in the simulation of its thermoelectric properties. INTRODUCTIONCobalt monosilicide CoSi is one of the most promising materials for creating thermogenerators, which is caused by the relatively high efficiency of CoSi-based thermogenerators and the physicochemical and mechanical properties of this compound (which are appropriate for technical applications) [1-3]. Nevertheless, many important thermal and elastic properties of CoSi are poorly understood. For example, the experimental data on the CoSi density are restricted to its room-temperature value, and experimental data on the heat capacity, the elastic moduli, and the thermal expansion coefficient are known for a relatively narrow temperature range [4][5][6][7]. The authors of [7] used the density functional theory (DFT) and the Debye model to calculate the properties of CoSi as functions of temperature and pressure. Nevertheless, the results presented in [7] do not agree with the experimental data quantitatively, which can be caused by the fact that the quasi-harmonic approximation used in [7] cannot take into account the effects related to phonon anharmonicity. However, according to the neutron diffraction data in [8], the phonon spectra of iron or cobalt monosilicide are characterized by an anomalously strong anharmonicity.The purpose of this work is to develop a self-consistent thermodynamic model for CoSi to take into account the influence of phonon anharmonicity on its thermal properties. Using this model, we were able to achieve quantitative agreement with the existing experimental data and to perform a self-consistent simulation of the temperature dependences of the lattice components of the heat capacity, the bulk com-

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“…Tellurium was found to be an appropriate metal flux for the growth of CoSi which yields high-quality single crystals with large magneto-resistance (MR) and carrier mobilities. Although there is plenty of research work on the thermopower of CoSi [16][17][18][19][20][21][28][29][30][31][32], few of them have paid attention to its magneto-Seebeck and Nernst effect.…”

Section: Introductionmentioning

confidence: 99%

Crystal growth and quantum oscillations in the topological chiral semimetal CoSi

Wang

Cochran

et al. 2019

Phys. Rev. B

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We survey the electrical transport properties of the single-crystalline, topological chiral semimetal CoSi which was grown via different methods. High-quality CoSi single crystals were found in the growth from tellurium solution. The sample's high carrier mobility enables us to observe, for the first time, quantum oscillations (QOs) in its thermoelectrical signals. Our analysis of QOs reveals two spherical Fermi surfaces around the R point in the Brillouin zone corner. The extracted Berry phases of these electron orbits are consistent with the −2 chiral charge as reported in DFT calculations. Detailed analysis on the QOs reveals that the spin-orbit coupling induced band-splitting is less than 2 meV near the Fermi level, one order of magnitude smaller than our DFT calculation result. We also report the phonon-drag induced large Nernst effect in CoSi at intermediate temperatures.

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High thermoelectric power factor in alloys based on CoSi

Cited by 46 publications

References 15 publications

Optimization of thermoelectric performance of SrSi2-based alloys via the modification in band structure and phonon-point-defect scattering

Optimization of thermoelectric performance of SrSi2-based alloys via the modification in band structure and phonon-point-defect scattering

Thermodynamic simulation of the elastic and thermal properties of cobalt monosilicide

Crystal growth and quantum oscillations in the topological chiral semimetal CoSi

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