Enabling Ab Initio Molecular Dynamics under Bias: The CP2K+SMEAGOL Interface for Integrating Density Functional...

Area of Science:

• Computational Physics
• Materials Science
• Quantum Chemistry

Background:

• Density Functional Theory (DFT) and Non-Equilibrium Green's Functions (NEGF) are crucial for modeling quantum transport.
• Accurate simulations of quantum transport under bias are computationally demanding.
• Existing tools lack comprehensive features for large-scale condensed phase systems.

Purpose of the Study:

• To introduce a novel interface between CP2K and SMEAGOL for enhanced DFT-NEGF calculations.
• To implement and validate current-induced forces within the CP2K+SMEAGOL framework.
• To demonstrate the capability of DFT-NEGF for molecular dynamics simulations of condensed phase systems under bias.

Main Methods:

• Developed a new interface connecting the CP2K electronic structure package with the SMEAGOL NEGF code.
• Implemented current-induced forces for simulating bias-driven dynamics.
• Validated the interface using a 1D Au wire, parallel-plate capacitor, and a Au-H2-Au junction.

Main Results:

• Achieved good agreement between CP2K+SMEAGOL and SIESTA-based NEGF calculations.
• Successfully demonstrated molecular dynamics simulations of a solvated Au wire under bias.
• The new interface is the most feature-rich DFT-NEGF implementation for CP2K to date.

Conclusions:

• The CP2K+SMEAGOL interface provides a powerful and efficient tool for quantum transport studies.
• This work enables, for the first time, DFT-NEGF molecular dynamics for large condensed phase systems under realistic operating conditions.
• The developed interface significantly advances the simulation of nanoscale electronic devices and materials.