Disordered zinc in Zn4Sb3 with phonon-glass and electron-crystal thermoelectric properties

Snyder, G. Jeffrey; Christensen, Mogens; Nishibori, Eiji; Caillat, T.; Iversen, Bo B.

doi:10.1038/nmat1154

Cited by 813 publications

(764 citation statements)

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“…[1][2][3] The TE performance of a material is characterized by its dimensionless thermoelectric figure of merit ZT = S 2 T/ρκ, where S is the Seebeck coefficient, T the absolute temperature, ρ the electrical resistivity, and κ the total thermal conductivity. Great effort has been expended in materials research and optimization utilizing the concepts of phonon-glass electron-crystal compounds (PGEC), [4][5][6] nano-inclusion materials, 7,8 and investigating compounds with complex crystal structures 9,10 with the goal of achieving high ZT TE materials.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

et al. 2011

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In this study, we have synthesized a series of low thermal conductivity diamond-like materials with the general formula Cu 2 Ga x Ge 1-x Se 3 for 0 ≤ x ≤ 0.1, and their transport properties were evaluated to establish their suitability for TE based waste heat recovery applications. We report results for the Seebeck coefficient (S), electrical resistivity (ρ), thermal conductivity (κ), Hall coefficient (R H ), crystal structure, and elastic properties of Cu 2 Ga x Ge 1-x Se 3 for x = 0.01, 0.03, 0.05, 0.07 and 0.1. Powder x-ray diffraction revealed that a small amount of a related cubic polymorph appeared along with the orthorhombic parent phase at high Ga concentrations. This cubic phase is related to the parent phase in that both contain three-dimensional tetrahedral diamond-like substructures. All samples showed positive values of S and R H over the entire temperature range studied, indicative of p-type charge carriers. The largest value of S = 446 μVK -1 was observed at 745 K for undoped Cu 2 GeSe 3 . With increasing Ga content, both S and ρ decreased. Low values of κ were observed for all samples with the lowest value of κ = 0.67 W m -1 K -1 at 745 K for undoped Cu 2 GeSe 3 . This value approaches the theoretical minimum thermal conductivity for these materials at high temperatures. Although this diamondlike material has highly symmetric, lower coordination number tetrahedral bonding, an unusually large Grüneisen parameter (γ), a measure of bonding anharmonicity, was observed for Cu 2 Ga 0.1 Ge 0.9 Se 3 . A value of γ = 1.7 was calculated from the measured values of the elastic properties, heat capacity, and volume thermal expansion. Given the fact that all materials investigated have similar elastic property values and likely comparable coefficients of thermal expansion we surmise that this large Grüneisen parameter is a general feature for this material system. We conclude that this high level of anharmonicity gives rise to enhanced phononphonon scattering that is, in addition to the scattering brought about by the disordered structure, resulting in very low values of thermal conductivity.

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Section: Introductionmentioning

confidence: 99%

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

et al. 2011

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“…1,2 The efficiency of such materials is determined by the thermoelectric figure of merit ZT = a 2 rT/j with a being the Seebeck coefficient, r the electrical conductivity, j the thermal conductivity, and T the absolute temperature. High ZT values can be expected neither for insulators, which show low electrical conductivity r, nor for metals with low thermopower a.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties of Polycrystalline SrZn2Sb2 Prepared by Spark Plasma Sintering

Zhang

Tang

Schnelle

et al. 2010

Journal of Elec Materi

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Compact polycrystalline samples of SrZn 2 Sb 2 [space group P3m1, a = 4.503(1) Å , c = 7.721(1) Å ] were prepared by spark plasma sintering. Thermoelectric performance, Hall effect, and magnetic properties were investigated in the temperature range from 2 K to 650 K. The thermoelectric figure of merit ZT was found to increase with temperature up to ZT = 0.15 at 650 K. At this temperature the material showed a high Seebeck coefficient of +230 lV K À1 , low thermal conductivity of 1.3 W m À1 K À1 , but rather low electrical conductivity of 54 S cm À1 , together with a complex temperature behavior. SrZn 2 Sb 2 is a diamagnetic p-type conductor with a carrier concentration of 5 9 10 18 cm À3 at 300 K. The electronic structure was calculated within the density-functional theory (DFT), revealing a low density of states (DOS) of 0.43 states eV À1 cell À1 at the Fermi level.

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“…3,14 Configurational arrangements of Zn 8 Sb 7 are much more difficult to enumerate appropriately without guidance from experimentally known defect lattice sites. The configurational disorder then was probed by a systematic enumeration of new possible configurations on the Zn sublattice.…”

Section: ' Computational Methodsmentioning

confidence: 99%

Predicted Electronic and Thermodynamic Properties of a Newly Discovered Zn₈Sb₇ Phase

et al. 2011

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A new binary compound, Zn8Sb7, has recently been prepared in nanoparticulate form via solution synthesis. No such phase is known in the bulk phase diagram; instead, one would expect phase separation to the good thermoelectric semiconductors ZnSb and Zn4Sb3. Here, density functional calculations are employed to determine the free energies of formation, including effects from vibrations and configurational disorder, of the relevant phases, yielding insight into the phase stability of Zn8Sb7. Band structure calculations predict Zn8Sb7, much like ZnSb and Zn4Sb3, to be an intermetallic semiconductor with similar thermoelectric properties. If sufficient entropy or surface energy exists to stabilize the bulk material, it would be stable in a limited temperature window at high temperature.

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Disordered zinc in Zn4Sb3 with phonon-glass and electron-crystal thermoelectric properties

Cited by 813 publications

References 19 publications

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

Thermoelectric Properties of Polycrystalline SrZn2Sb2 Prepared by Spark Plasma Sintering

Predicted Electronic and Thermodynamic Properties of a Newly Discovered Zn₈Sb₇ Phase

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Disordered zinc in Zn4Sb3 with phonon-glass and electron-crystal thermoelectric properties

Cited by 813 publications

References 19 publications

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

Thermoelectric Properties of Polycrystalline SrZn2Sb2 Prepared by Spark Plasma Sintering

Predicted Electronic and Thermodynamic Properties of a Newly Discovered Zn8Sb7 Phase

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Product

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Predicted Electronic and Thermodynamic Properties of a Newly Discovered Zn₈Sb₇ Phase