openmaterials.ai / codes / AMSET
Scattering rates for anisotropic semiconductors from materials parameters alone, with no DFPT electron-phonon step, at about 1/500th the cost of DFPT plus Wannier (Ganose 2021).
Acoustic deformation potential, piezoelectric, ionized impurity and polar optical phonon matrix elements, each extended to the full elastic, piezoelectric and dielectric tensors, feed the Boltzmann transport equation.
Acoustic strain comes from the Christoffel equation with the full elastic tensor, so the longitudinal and both transverse modes enter one matrix element.
PBE bands on a uniform k mesh, wave functions, elastic, dielectric and piezoelectric tensors, deformation potentials and a polar phonon frequency.
A modified linear tetrahedron scheme puts hundreds of points on each cross section's energy-conserving surface and handles the 1/q^4 impurity singularity (Ganose 2021).
Band- and k-resolved lifetimes, mobility in cm^2/(V s), conductivity in S/m, Seebeck coefficient in muV/K and electronic thermal conductivity in W/(m K).
The mobility of NbFeSb and Ba2BiAu took 29 core hours against 8350 for DFPT plus Wannier. The transport step alone runs in under an hour on a laptop (Ganose 2021).
AMSET gives a room temperature electron mobility of 18.2 cm^2/(V s) at 4e18 cm^-3, limited by polar optical phonons. With kappa_L below 0.1 W/(m K), ZT reaches 2.57 at 600 K. Jung 2021
At 300 K AMSET mobilities average about 40 cm^2/(V s) for electrons and 15 for holes, limited by polar optical phonons, consistent with large polarons rather than self-trapping. Wang 2022
PbCuSeF, PbAgSeF and PbAgTeF lie within 25 meV/atom of the hull with kappa_L below 1 W/(m K). AMSET gives them higher power factors than their Ba analogs. He 2021
Relax, then a uniform non-self-consistent run at 1000 k-points/A^3 for bands and states.
Elastic, dielectric and piezoelectric tensors, deformation potentials, phonon frequency.
Temperatures and carrier concentrations, and a scissor to the HSE06 gap if wanted.
Interpolate with BoltzTraP2, integrate each mechanism over q with the tetrahedron scheme.
Mobility, conductivity, Seebeck and electronic thermal conductivity at each T and doping.