CAREER: Investigating Strong Electron-Phonon Interactions in Semiconducting Crystals Using Reciprocal-Space Quantum-Classical Modeling

We propose to develop the theoretical methodology required to dynamically model strong electron-phonon interactions in crystalline materials at affordable computational cost, and to apply this methodology to study how electron-phonon coupling impacts the dynamics and valleytronic behavior of electronic carriers in monolayer transition-metal dichalcogenides and exciton absorption and dissociation in bulk metal-halide perovskites. Both of these emergent semiconducting materials feature a coupling of carriers to phonons that is significantly stronger than that found for other inorganic crystals, and which is at the heart of the photophysical properties that render them of exceptional technological interest. While realizing the possibility to model their effects nonperturbatively, we will quantitatively address a range of compelling open questions such as the debated origin of valley depolarization in transition-metal dichalcogenides and the functional relevance of the recently-detected chiral phonon modes of its hexagonal lattice. For metal-halide perovskites, it will enable us to model the entire process ranging from photoexcitation to exciton dissociation and recombination based on uniform principles, through which the design rules responsible for observed high photoconversion efficiencies can be identified.