Synthesis and thermoelectric properties of the (GeTe)1-x(PbTe)x alloys

Li, S.P.; Li, J.Q.; Wang, Q.B.; Wang, L.; Liu, F.S.; Ao, W.Q.

doi:10.1016/j.solidstatesciences.2010.11.045

Cited by 52 publications

(26 citation statements)

References 19 publications

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“…Low thermal conductivity and high figure of merit have been recently reported in (Pb,Ge)Te materials with phase separated regions and nanoscale features [56][57][58]. Since no dips in the κ values close to the transition temperature have been observed in these materials, their κ reduction is likely dominated by phonon scattering at the interfaces.…”

Section: Discussionmentioning

confidence: 94%

Broadband phonon scattering in PbTe-based materials driven near ferroelectric phase transition by strain or alloying

et al. 2016

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The major obstacle in the design of materials with low lattice thermal conductivity is the difficulty in efficiently scattering phonons across the entire frequency spectrum. Using first principles calculations, we show that driving PbTe materials to the brink of the ferroelectric phase transition could be a powerful strategy to solve this problem. We illustrate this concept by applying tensile [001] strain to PbTe and its alloys with another rock-salt IV-VI material, PbSe; and by alloying PbTe with a rhombohedral IV-VI material, GeTe. This induces extremely soft optical modes at the zone center, which increase anharmonic acoustic-optical coupling and decrease phonon lifetimes at all frequencies. We predict that PbTe, Pb(Se,Te) and (Pb,Ge)Te alloys driven close to the phase transition in the described manner will have considerably lower lattice thermal conductivity than that of PbTe (by a factor of 2 − 3). The proposed concept may open new opportunities for the development of more efficient thermoelectric materials.

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Section: Discussionmentioning

confidence: 94%

Broadband phonon scattering in PbTe-based materials driven near ferroelectric phase transition by strain or alloying

et al. 2016

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“…These alloys undergo a soft optical mode transition between the rocksalt and rhombohedral phases as a function of the composition and temperature [23], and have high ZT [19,20,[24][25][26][27]. Our first principles virtual-crystal calculations show that the phase transition minimizes the anharmonic component of κ due to extremely soft optical modes which maximize the anharmonic acoustic-optical coupling, especially for lowfrequency phonons.…”

Section: Introductionmentioning

confidence: 80%

Ferroelectric phase transition and the lattice thermal conductivity of Pb1−xGexTe alloys

et al. 2017

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Type of publicationArticle (peer-reviewed) We show how tuning the proximity to the soft optical mode phase transition via chemical composition affects the lattice thermal conductivity κ of Pb 1−x Ge x Te alloys. Using first-principles virtual-crystal simulations, we find that the anharmonic contribution to κ is minimized at the phase transition due to the maximized acoustic-optical anharmonic interaction. Mass disorder significantly lowers and flattens the dip in the anharmonic κ over a wide composition range, thus shifting the κ minimum away from the phase transition. The total κ and its anharmonic contribution vary continuously between the rocksalt and rhombohedral phases as expected for the second-order phase transition. The actual phase and its strength of resonant bonding play a less prominent role in reducing the κ of Pb 1−x Ge x Te alloys than the proximity to the phase transition and the atomic mass. Our results show that alloys with soft optical mode transitions are promising materials for achieving low thermal conductivity and possibly high thermoelectric efficiency.

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“…The layer mixing of heterostructure is promising for enhancing thermoelectric (TE) properties, i.e., the figure of merit ZT = S 2 σT/ρκ, where S is the Seebeck coefficient, σ is the electrical conductivity, κ is the thermal conductivity, and T is the absolute temperature [1][2][3][4][5][6][7][8][9]. Intrinsic interface effect modifies the electrical properties by altering the band structures and the bandgap energy.…”

Section: Introductionmentioning

confidence: 99%

OptimizedZTofBi2Te3−GeTecompoun

2016

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We predict the thermoelectric properties of layered [GeTe] m [Bi 2 Te 3 ] n (GBT) compounds (1 ≤ m ≤ 8, 1 ≤ n ≤ 3), using first-principles-Boltzmann transport calculations of the homogeneous (Bi 2 Te 3 and GeTe) data. The lattice strain and the quantum-confinement effects of compounds evolve the bandgap structures, resulting in asymmetric and large Seebeck coefficient, at high GeTe content.Using semi-empirical calculations of electron scattering rate 1/ ! , dominated by electron-acoustic phonon scattering, we reproduce reported TE properties of GBT compounds. We predict that due to small Seebeck coefficient, the GBT compounds with high n-and p-type doping (~10 20 cm -3 ), do not have high ZT near room temperature. However, we predict that the moderately-doped (~10 19 cm -3 ), p-type GBT compounds have enhanced ZT ≈ 1.4 near room temperature. *

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Synthesis and thermoelectric properties of the (GeTe)1-x(PbTe)x alloys

Cited by 52 publications

References 19 publications

Broadband phonon scattering in PbTe-based materials driven near ferroelectric phase transition by strain or alloying

Broadband phonon scattering in PbTe-based materials driven near ferroelectric phase transition by strain or alloying

Ferroelectric phase transition and the lattice thermal conductivity of Pb1−xGexTe alloys

OptimizedZTofBi2Te3−GeTecompoun

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