Real-Space Quantification of Exciton Localization in Acene Crystals Using Wannier Function Decomposition

Area of Science:

• Condensed matter physics
• Quantum chemistry
• Materials science

Background:

• Exciton localization is crucial for understanding optical and electronic properties of solids.
• Accurate quantification of exciton behavior requires advanced theoretical methods.
• Current methods may lack spatial resolution or be computationally intensive.

Purpose of the Study:

• To introduce a novel real-space method, Wannier function decomposition of excitons (WFDX), for quantifying exciton localization.
• To provide orbital- and spatial-resolved measures of exciton properties.
• To explore the computational efficiency and applicability of WFDX.

Main Methods:

• Utilizing the ab initio Bethe-Salpeter equation framework.
• Decomposing Bloch exciton wave functions into maximally localized Wannier functions for electrons and holes.
• Applying the WFDX method to analyze excitons in acene crystals.

Main Results:

• WFDX provides well-defined, low-cost measures of Frenkel and charge-transfer excitons in real space.
• The study quantifies the impact of molecular size, spin state, and momentum on exciton localization in acenes.
• WFDX reveals hidden nonsymmorphic symmetries and facilitates reciprocal-space interpolation.

Conclusions:

• WFDX is an efficient and versatile tool for analyzing and computing excitonic properties in solids.
• The method enhances understanding of exciton behavior and its relation to material structure.
• WFDX opens new avenues for investigating excitonic phenomena and material design.