Anharmonicity and atomic distribution of SnTe and PbTe thermoelectrics

Li, Chen W.; Ma, Jisheng; Cao, Huibo; May, Andrew F.; Abernathy, D. L.; Ehlers, Georg; Hoffmann, Christina; Wang, Xiaoping; Hong, Tao; Huq, Ashfia; Gourdon, Olivier; Delaire, Olivier

doi:10.1103/physrevb.90.214303

Cited by 77 publications

(66 citation statements)

References 56 publications

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“…A clear theoretical explanation of the anomalous stiffening of the LO mode with increasing temperature was only given last year by Li et al 13 . At the same time, there is a very strong anharmonicity between the ferroelectric transverse mode and the longitudinal acoustic mode, which was studied in part by Li et al in a follow up paper 21 .…”

Section: -4mentioning

confidence: 94%

Thermal conductivity in PbTe from first principles

et al. 2015

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We investigate the harmonic and anharmonic contributions to the phonon spectrum of lead telluride, and perform a complete characterization of how the anharmonic effects dominate the phonons in PbTe as temperature increases. This effect is the strongest factor in the favorable thermoelectric properties of PbTe: an optical-acoustic phonon band crossing reduces the speed of sound and the intrinsic thermal conductivity. We present the detailed temperature dependence of the dispersion relation and compare our calculated neutron scattering cross section with recent experimental measurements. We analyze the thermal resistivity's variation with temperature and clarify misconceptions about existing experimental literature. This quantitative prediction opens the way to phonon phase space engineering, to tailor the lifetimes of crucial heat carrying phonons.

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Section: -4mentioning

confidence: 94%

Thermal conductivity in PbTe from first principles

et al. 2015

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“…Among thermoelectrics, PbTe and SnTe have drawn attention due to some of their interesting properties [12][13][14][15][16][17] . Both systems have high figures of merit, turning them into effective thermoelectrics.…”

Section: Introductionmentioning

confidence: 99%

Strong anharmonicity in the phonon spectra of PbTe and SnTe from first principles

et al. 2018

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At room temperature, PbTe and SnTe are efficient thermoelectrics with a cubic structure. At low temperature, SnTe undergoes a ferroelectric transition with a critical temperature strongly dependent on the hole concentration, while PbTe is an incipient ferroelectric. By using the stochastic self-consistent harmonic approximation, we investigate the anharmonic phonon spectra and the occurrence of a ferroelectric transition in both systems. We find that vibrational spectra strongly depends on the approximation used for the exchange-correlation kernel in density functional theory. If gradient corrections and the theoretical volume are employed, then the calculation of the free energy Hessian leads to phonon spectra in good agreement with experimental data for both systems. In PbTe, we reproduce the transverse optical mode phonon satellite detected in inelastic neutron scattering and the crossing between the transverse optical and the longitudinal acoustic modes along the ΓX direction. In the case of SnTe, we describe the occurrence of a ferroelectric transition from the high temperature Fm3m structure to the low temperature R3m one.

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“…Classical MD simulations of 512-atom supercells based on ab initio inter-atomic force constants (IFCs) 13 also reproduced the phonon spli ing and identi ed unusually large cubic IFCs along the ⟨100⟩ direction as the source. In contrast, later studies 14,15 combining ab initio MD simulations (using 512 atom supercells and the PBE functional in the VASP code) with single-crystal and powder neutron di raction and inelastic neutron sca ering suggested that a sharp resonance in the phonon self energy caused by nesting of phonon dispersions could combine with the anharmonicity to produce the large phonon spli ing. Once again, however, while the simulated nearest-neighbor Pb-Te PDF peak showed increasing asymmetric character with temperature, the highly-non-Gaussian lineshapes and anomalous shi s in peak centroid were not captured.…”

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confidence: 99%

Correlated local dipoles in PbTe

Sangiorgio

Božin

Malliakas

et al. 2018

Phys. Rev. Materials

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We present a combined single-crystal x-ray di use sca ering and ab-initio molecular dynamics study of lead telluride, PbTe. Well-known for its thermoelectric and narrow-gap semiconducting properties, PbTe recently achieved further notoriety following the report of an unusual o -centering of the lead atoms, accompanied by a local symmetry breaking, on heating. is observation, which was named emphanisis, ignited considerable controversy regarding the details of the underlying local structure and the appropriate interpretation of the total sca ering experiments. In this study, we demonstrate close agreement between our di use sca ering measurements and our calculations, which allows us to analyze features such as higher-order correlations that are accessible in the simulations but not experimentally. is allowed us to discover an unusual correlated local dipole formation extending over several unit cells with an associated local reduction of the cubic symmetry in both our x-ray di use sca ering measurements and our molecular dynamics simulations. Importantly, when averaged spatially or temporally, the most probable positions for the ions are at the centers of their coordination polyhedra. Our results therefore clarify the nature of the local symmetry breaking, and reveal the source of the earlier controversy regarding the existence or absence of o -centering. Finally, we provide an interpretation of the behavior in terms of coupled so optical and acoustic modes, which is linked also to the high thermoelectric performance of PbTe.

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Anharmonicity and atomic distribution of SnTe and PbTe thermoelectrics

Cited by 77 publications

References 56 publications

Thermal conductivity in PbTe from first principles

Thermal conductivity in PbTe from first principles

Strong anharmonicity in the phonon spectra of PbTe and SnTe from first principles

Correlated local dipoles in PbTe

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