Trion-phonon interaction in atomically thin semiconductors

Abstract

Optical and transport properties of doped monolayer semiconductors are dominated by trions, which are three-particle compounds formed by two electrons and one hole or vice versa. In this work, we investigate the trion-phonon interaction on a microscopic footing and apply our model to the exemplary case of a molybdenum diselenide (MoSe2) monolayer. We determine the trion series of states and their internal quantum structure by solving the trion Schrödinger equation. Transforming the system into a trion basis and solving equations of motion, including the trion-phonon interaction within the second-order Born-Markov approximation, provides a microscopic access to the trion dynamics. In particular, we investigate trion propagation and compute the diffusion coefficient and mobility. In the low density limit, we find that trions propagate less efficiently than excitons and electrons due to their stronger coupling with phonons and their larger mass. For increasing densities, we predict a drastic enhancement of diffusion caused by the build-up of a large pressure by the degenerate trion gas, which is a direct consequence of the fermionic character of trions. Our work provides microscopic insights into the trion-phonon interaction and its impact on the diffusion behaviour in atomically thin semiconductors.

References in corpus (16)

• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Intrinsic Transport Properties of Electrons and Holes in Monolayer Transition Metal Dichalcogenides
• Trion induced negative photoconductivity in monolayer MoS2
• Many-Body Theory of Trion Absorption Features in Two-Dimensional Semiconductors
• Valley Phonons and Exciton Complexes in a Monolayer Semiconductor
• Long-Lived Valley Polarization of Intra-Valley Trions in Monolayer WSe2
• Hot-electron cooling by acoustic and optical phonons in monolayers of MoS${}_2$ and other transition-metal dichalcogenides
• Electron-exciton interactions in the exciton-polaron problem
• Intrinsic Lifetime of Higher Excitonic States in Tungsten Diselenide Monolayers
• Nonclassical Exciton Diffusion in Monolayer WSe2
• Ground and Excited Exciton Polarons in Monolayer MoSe2
• A Many-Body Theory of the Optical Conductivity of Excitons and Trions in Two-Dimensional Materials
• Phonon-assisted exciton and trion conversion efficiency in transition metal Dichalcogenides
• Excitonic theory of doping-dependent optical response in atomically thin semiconductors
• Exciton diffusion in a hBN-encapsulated monolayer MoSe2
• Imaging Seebeck drift of excitons and trions in MoSe2 monolayers