SAKE: first-principles electron transport calculation code.

Area of Science:

• Computational Physics
• Materials Science
• Quantum Chemistry

Background:

• Accurate simulation of electron transport is crucial for designing novel electronic materials.
• First-principle calculations offer a robust framework for understanding material properties.
• Non-equilibrium Green's function formalism is essential for open quantum systems.

Purpose of the Study:

• To develop and present a numerical code, SAKE (simulation code for atomistic Kohn-Sham equation), for first-principle electron transport calculations.
• To detail the computational techniques employed for electronic states and transport properties in open, non-equilibrium systems.
• To demonstrate the code's applicability through calculations on diverse material systems.

Main Methods:

• Density-functional theory (DFT) combined with non-equilibrium Green's function (NEGF) formalism.
• Development of a numerical code (SAKE) implementing these theoretical frameworks.
• Specific computational techniques including complex contour integration for charge density and efficient self-consistent procedures.

Main Results:

• Analysis of electronic structures in polythiophene molecular wires, comparing density matrix summation techniques.
• Investigation of thermoelectric properties (conductance, Seebeck coefficient) in CuFeS2.
• Examination of electron transport in polyaniline molecular wires under structural deformations, showing temperature-dependent current behavior.

Conclusions:

• The SAKE code provides a versatile tool for first-principle electron transport simulations.
• The study demonstrates the code's capability in analyzing diverse material systems, from molecular wires to semiconductors.
• Results highlight the interplay between thermal and electronic energies in determining transport properties.