Material Descriptors for the Discovery of Efficient Thermoelectrics

Graziosi, Patrizio; Kumarasinghe, Chathurangi; Neophytou, Neophytos

doi:10.1021/acsaem.0c00825

Cited by 46 publications

(88 citation statements)

References 67 publications

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“…This allows for effective k-point mesh densities that would be almost impossible to achieve with uniform k-point sampling (the full methodology is provided in the Supplementary Methods). While other works have used similar matrix elements 60 , we extend these approaches by considering interband scattering and first-principles wave function overlaps in the evaluation of Coulomb-based impurity scattering. In Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

Efficient calculation of carrier scattering rates from first principles

et al. 2021

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The electronic transport behaviour of materials determines their suitability for technological applications. We develop a computationally efficient method for calculating carrier scattering rates of solid-state semiconductors and insulators from first principles inputs. The present method extends existing polar and non-polar electron-phonon coupling, ionized impurity, and piezoelectric scattering mechanisms formulated for isotropic band structures to support highly anisotropic materials. We test the formalism by calculating the electronic transport properties of 23 semiconductors, including the large 48 atom CH3NH3PbI3 hybrid perovskite, and comparing the results against experimental measurements and more detailed scattering simulations. The Spearman rank coefficient of mobility against experiment (rs = 0.93) improves significantly on results obtained using a constant relaxation time approximation (rs = 0.52). We find our approach offers similar accuracy to state-of-the art methods at approximately 1/500th the computational cost, thus enabling its use in high-throughput computational workflows for the accurate screening of carrier mobilities, lifetimes, and thermoelectric power.

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Section: Resultsmentioning

confidence: 99%

Efficient calculation of carrier scattering rates from first principles

et al. 2021

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“…Distinctively, as discussed above, interband POS reduces α because it preferentially scatters higher energy states of both bands during convergence. Of note, ionized-impurity scattering (IIS) similarly cannot couple distant states because where γ is inverse screening distance 35 , 54 . Furthermore, in systems with inversion symmetry, it is known that interband DPS between symmetry-degenerate band pockets could be prohibited, for any phonon mode, by parity relations 55 .…”

Section: Resultsmentioning

confidence: 99%

“…A related concern is the relative location of band pockets in the Brillouin zone. Band pockets that are distant in reciprocal space are typically subject to weaker scattering overall 1 , 35 and, in certain cases, parity restrictions may further weaken intervalley transitions between distant symmetry-degenerate pockets 36 . In contrast, when multiple distinct bands are at the same k-point, there is little reason to presume that interband scattering would not possibly negate the benefit of band convergence.…”

Section: Introductionmentioning

confidence: 99%

When band convergence is not beneficial for thermoelectrics

et al. 2021

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Band convergence is considered a clear benefit to thermoelectric performance because it increases the charge carrier concentration for a given Fermi level, which typically enhances charge conductivity while preserving the Seebeck coefficient. However, this advantage hinges on the assumption that interband scattering of carriers is weak or insignificant. With first-principles treatment of electron-phonon scattering in the CaMg2Sb2-CaZn2Sb2 Zintl system and full Heusler Sr2SbAu, we demonstrate that the benefit of band convergence can be intrinsically negated by interband scattering depending on the manner in which bands converge. In the Zintl alloy, band convergence does not improve weighted mobility or the density-of-states effective mass. We trace the underlying reason to the fact that the bands converge at a one k-point, which induces strong interband scattering of both the deformation-potential and the polar-optical kinds. The case contrasts with band convergence at distant k-points (as in the full Heusler), which better preserves the single-band scattering behavior thereby successfully leading to improved performance. Therefore, we suggest that band convergence as thermoelectric design principle is best suited to cases in which it occurs at distant k-points.

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“…The values of deformation potential used for ADP (eV), ODP (eV/ Å), IVS (eV/ Å) and phonon frequencies (meV) are listed in Table III. All the transport calculations are conducted using our owndeveloped Boltzmann transport equation simulator Elec-Tra [99], whose details can be found in the previous papers [20,43,44,100], which discretizes the 3D dispersion and constructs scattering times for every transport state using the derived deformation potentials.…”

Section: Transport Propertiesmentioning

confidence: 99%

“…These can then be used, for example, within device transport simulators [40,41], and in general when e-ph scattering needs to be combined with other scattering mechanisms, such as for nanostructured materials [42], or highly doped materials and alloys for which ionized impurity scattering [43] and alloy scattering are important. Such methods are routinely employed for transistor devices and thermoelectric materials [44]. The use of deformation potentials can allow for the flexibility and computational robustness that these simulators require.…”

Section: Introductionmentioning

confidence: 99%