𝐴𝑏 initio density-matrix approach to exciton coherence: Phonon scattering, Coulomb interactions, and radiative recombination

Journal Article · Mon Sep 29 00:00:00 EDT 2025 · Physical Review. B

DOI:https://doi.org/10.1103/phvn-cd52· OSTI ID:3007579

Amit, Tomer ^[1]; Vosco, Guy ^[1]; Ben, Mauro Del ^[2]; Refaely-Abramson, Sivan ^[1]

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1. Weizmann Institute of Science, Rehovot (Israel)
2. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Relaxation processes following light excitation in semiconductors are key in materials-based quantum technology applications. These processes are broadly studied in atomically thin transition-metal dichalcogenides, quasi-two-dimensional excitonic semiconductors in which atomistic design allows for tunable excited-state properties, such as relaxation lifetimes and photoinduced coherence. In this work, we present a density-matrix-based approach to compute exciton relaxation within a many-body ab initio perspective. We expand our previously developed Lindblad density-matrix formalism to capture multichannel electron-hole pair relaxation processes, including phonon and Coulomb scattering as well as radiative recombination, and we study their effect on the time-resolved excited-state propagation. Using monolayer MoSe₂ as a prototypical example, we examine many-body effects on the time-dependent dynamics of photoactive excitations, exploring how the electron-hole pair interactions are reflected in variations of the excitation energy, spectral signature, and state coherence. In conclusion, our method supplies a detailed understanding of exciton relaxation mechanisms in realistic materials, offering a previously unexplored pathway to study excited-state dynamics in semiconductors from first principles.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: H2020 European Research Council; Israel Science Foundation; Minerva Foundation; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 3007579
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 11 Vol. 112; ISSN 2469-9950; ISSN 2469-9969
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

Band structure methods
Bethe-Salpeter equation
Density matrix methods
Excitons
First-principles calculations
GW method
Quantum coherence & coherence measures
Transition metal dichalcogenides