High Thermoelectric Performance and Defect Energetics of Multi-pocketed Full-Heusler Compounds
arXiv:2003.05506 · doi:10.1103/PhysRevApplied.14.024064
Abstract
We report first-principles density-functional study of electron-phonon interactions and thermoelectric transport properties of full-Heusler compounds SrBiAu and SrSbAu. Our results show that ultrahigh intrinsic bulk thermoelectric performance across a wide range of temperatures is physically possible and point to the presence of multiply degenerate and highly dispersive carrier pockets as the key factor for achieving it. SrBiAu, which features ten energy-aligned low effective mass pockets (six along and four at ), is predicted to deliver -type at ~K. Comparison with the previously investigated BaBiAu compound shows that the additional -pockets in SrBiAu significantly increase its low-temperature power factor to a maximum value of ~mW~m~K near ~K. However, at high temperatures the power factor of SrBiAu drops below that of BaBiAu because the states are heavier and subject to strong scattering by phonon deformation as opposed to the lighter states that are limited by polar-optical scattering. SrSbAu is predicted to deliver lower -type of at ~K due to appreciable misalignment between the and carrier pockets, generally heavier scattering, and slightly higher lattice thermal conductivity. Soft acoustic modes, responsible for low lattice thermal conductivity, also increase vibrational entropies and high-temperature stability of the Heusler compounds, suggesting that their experimental synthesis may be feasible. The dominant intrinsic defects are found to be Au vacancies, which drive the Fermi level towards the conduction band and work in favor of -doping.
References in corpus (20)
- Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
- Advanced capabilities for materials modelling with Quantum ESPRESSO
- BoltzTraP. A code for calculating band-structure dependent quantities
- Maximally-localized generalized Wannier functions for composite energy bands
- Wannier90: A Tool for Obtaining Maximally-Localised Wannier Functions
- Optimized norm-conserving Vanderbilt pseudopotentials
- Maximally-localized Wannier functions for entangled energy bands
- Electron-phonon interactions from first principles
- Optimization Algorithm for the Generation of ONCV Pseudopotentials
- EPW: Electron-phonon coupling, transport and superconducting properties using maximally localized Wannier functions
- EPW: A program for calculating the electron-phonon coupling using maximally localized Wannier functions
- Lattice anharmonicity and thermal conductivity from compressive sensing of first-principles calculations
- Quantum Čerenkov Effect from Hot Carriers in Graphene: An Efficient Plasmonic Source
- Fröhlich electron-phonon vertex from first principles
- Ultralow Thermal Conductivity in Full-Heusler Semiconductors
- Band-edge problem in the theoretical determination of defect energy levels: the O vacancy in ZnO as a benchmark case
- The temperature dependence of electronic eigenenergies in the adiabatic harmonic approximation
- Quantum-continuum simulation of underpotential deposition at electrified metal-solution interfaces
- Dominant electron-phonon scattering mechanisms in -type PbTe from first principles
- High -type thermoelectric power factor and efficiency in BaBiAu from a highly dispersive band