Real-Space Quantification of Exciton Localization in Crystals Using Wannier Function Decomposition
ORAL
Abstract
The degree of spatial localization of excitons in crystals is key for understanding absorption spectroscopy, exciton dynamics, and more. Here, we introduce the Wannier function decomposition of excitons (WFDX) method to quantify exciton localization in solids within the ab initio Bethe–Salpeter equation framework. By decomposing each Bloch exciton wavefunction into products of single-particle electron and hole maximally localized Wannier functions, this real-space approach provides well-defined orbital- and spatial- resolved measures of both Frenkel and charge-transfer excitons at low computational cost. We apply WFDX to excitons in acene crystals, quantifying how the number of rings, the exciton spin state, and the center-of-mass momentum affect spatial localization. Additionally, we demonstrate how this real-space representation reflects structural nonsymmorphic symmetries that are hidden in standard reciprocal space descriptions. We outline how the WFDX framework can be used to efficiently interpolate exciton expansion coefficients in reciprocal-space, facilitate evaluation of observables involving position operators and offer a direct route to study phase-dependent excited-state phenomena in real space, highlighting its potential as a general tool for both analyzing and computing excitonic properties in solids.
*This work was supported by the Center for Computational Study of Excited-State Phenomena in Energy Materials at LBNL, funded by the DOE, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. We acknowledge NERSC for providing computational resources.
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Publication: https://arxiv.org/abs/2510.06539
Presenters
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Zui Tao
- University of California, Berkeley
- Dept. of Chemistry, University of California, Berkeley; Materials Sciences Division, LBNL