Fröhlich Electron-Phonon Vertex from First Principles.

Area of Science:

• Condensed matter physics
• Materials science
• Computational physics

Background:

• Electron-phonon interactions are crucial for understanding material properties.
• Existing methods often struggle with anisotropic materials and multiple phonon branches.
• Accurate calculations are needed for predicting electronic behavior.

Purpose of the Study:

• To develop a first-principles method for calculating the electron-phonon vertex in polar semiconductors and insulators.
• To generalize the Fröhlich vertex for anisotropic materials and multiple phonon branches.
• To enable accurate ab initio calculations of carrier properties.

Main Methods:

• Developed a new formalism for the electron-phonon vertex.
• Generalized the Fröhlich vertex to anisotropic materials and multiple phonon branches.
• Applied the method as a postprocessing correction and with ab initio interpolation using maximally localized Wannier functions.

Main Results:

• Demonstrated the formalism by investigating electron-phonon interactions in anatase TiO(2).
• Showed that the polar vertex significantly reduces electron lifetimes.
• Observed enhanced anisotropy in electron-phonon coupling.

Conclusions:

• The developed method enables accurate ab initio calculations of carrier mobilities, lifetimes, mass enhancement, and pairing in polar materials.
• This work provides a significant advancement in understanding electron-phonon interactions in complex materials.
• The formalism is versatile, applicable as postprocessing or integrated with ab initio methods.