Frequency-domain multiscale quantum mechanics/electromagnetics simulation method.

Area of Science:

• Computational physics
• Quantum chemistry
• Electrical engineering

Background:

• Accurate simulation of electronic devices requires integrating quantum mechanics (QM) for molecular behavior and electromagnetics (EM) for device-level interactions.
• Existing time-domain QM/EM methods have limitations in capturing dynamic properties over broad operating frequencies.

Purpose of the Study:

• To develop and present a novel frequency-domain quantum mechanics and electromagnetics (QM/EM) method.
• To enhance the analysis of dynamic properties in electronic devices, particularly over a wider range of operating frequencies.

Main Methods:

• The developed method divides the system into distinct QM and EM regions.
• Self-consistent calculations are performed by iteratively updating boundary conditions at the QM/EM interface.
• Information exchange between QM and EM regions is facilitated by using interface potential and current densities as boundary conditions, ensuring continuity.

Main Results:

• The frequency-domain QM/EM method effectively captures dynamic properties over a broader frequency range compared to time-domain approaches.
• Continuous potential, charge, and current distributions are maintained across the QM/EM interface.
• Dynamic admittance was calculated and compared for a carbon nanotube molecular device using both time-domain and frequency-domain QM/EM methods.

Conclusions:

• The frequency-domain QM/EM method offers improved accuracy and broader applicability for simulating electronic devices.
• This approach provides a robust framework for understanding the interplay between quantum and electromagnetic phenomena in nanoscale devices.
• The method's ability to ensure interface continuity is crucial for reliable computational modeling.