Fermi Level Determination for Charged Systems via Recursive Density of States Integration

Area of Science:

• Computational Materials Science
• Condensed Matter Physics
• Quantum Chemistry

Background:

• Accurate Fermi level determination is crucial for understanding material electronic and chemical properties.
• Traditional ab initio methods struggle with charged systems due to ill-defined reference potentials from compensating background charges.
• Existing methods for charged systems often rely on localized compensating charges, which can introduce artifacts.

Purpose of the Study:

• To develop a robust method for calculating Fermi levels in charged periodic systems.
• To overcome the limitations of ill-defined vacuum potentials in ab initio calculations of charged materials.
• To provide a reliable approach for evaluating Fermi levels across a range of materials.

Main Methods:

• Developed a method based on recursively integrating the density of states (DOS).
• Introduced incremental charges to compute the DOS profile and track Fermi level shifts.
• Applied the method to various materials including graphene, h-BN, C3N4, Cu, and MoS2.

Main Results:

• The recursive DOS integration method accurately determines Fermi level shifts upon charging.
• The approach successfully handles systems where traditional methods face challenges with background charge potentials.
• Demonstrated reasonable agreement with established models, validating the new method's efficacy.

Conclusions:

• The developed method offers a reliable way to compute Fermi levels in charged periodic systems.
• This technique enhances the accuracy of electronic property predictions for materials under varying charge states.
• The approach provides a valuable tool for computational materials science research.