Time-dependent density functional theory for open systems with a positivity-preserving decomposition scheme for...

Area of Science:

• Condensed matter physics
• Computational materials science
• Quantum chemistry

Background:

• Understanding electron dynamics on material surfaces is crucial for advanced technologies like nanoelectronics, catalysis, and photovoltaics.
• Current methods, such as time-dependent density functional theory for open systems, face challenges in accurately capturing electronic structure and memory effects of the environment.
• Reliability and accuracy of simulations depend heavily on how the material's environment is modeled.

Purpose of the Study:

• To develop a novel and robust computational scheme for simulating electronic dynamics in materials.
• To improve the accuracy, convergence, and long-time stability of open-system electronic dynamics simulations.
• To provide a reliable method for studying electron dissipation in various material systems.

Main Methods:

• Development of a novel squared-Lorentzian decomposition scheme for environment spectral matrices.
• Ensuring the preservation of positive semi-definiteness of the environment spectral matrix.
• Applying the scheme to prototypical model systems, including atomic chains and bilayer graphene.

Main Results:

• The novel decomposition scheme guarantees accurate and convergent electronic dynamics, even in the long-time limit.
• Significant improvement in the long-time stability of electronic dynamics simulations.
• Demonstrated validity and usefulness through simulations on quasi-one-dimensional atomic chains and two-dimensional bilayer graphene.

Conclusions:

• The squared-Lorentzian decomposition scheme offers a significant advancement in simulating electronic dynamics.
• The method enhances the reliability and accuracy of computational approaches for open quantum systems.
• This work provides a valuable tool for research in nanoelectronics, catalysis, and photovoltaics.