Density-functional theory of thermoelectric phenomena

Area of Science:

• Condensed Matter Physics
• Theoretical Chemistry
• Materials Science

Background:

• Thermoelectric phenomena are crucial for energy conversion.
• Existing theories often struggle with local temperature variations.
• A robust theoretical framework is needed for nonequilibrium systems.

Purpose of the Study:

• Introduce a nonequilibrium density-functional theory (DFT) for local temperature.
• Develop a method to study thermoelectric phenomena.
• Incorporate local energy density as a fundamental variable.

Main Methods:

• Developed a DFT framework with a local temperature field.
• Introduced excess-energy density alongside particle density.
• Derived a novel Kohn-Sham equation with a temperature-dependent mass.
• Utilized linear response theory for transport coefficients.

Main Results:

• The theory successfully describes local temperature and energy density.
• A new Kohn-Sham equation captures dynamic temperature variations.
• Adiabatic potentials are linked to entropy functionals.
• The framework allows for the study of dissipation.

Conclusions:

• The proposed nonequilibrium DFT is suitable for thermoelectric studies.
• The novel Kohn-Sham approach offers insights into local temperature effects.
• This theory provides a foundation for understanding electron gas transport under thermal gradients.