Valley-selective energy transfer between quantum dots in atomically thin semiconductors

TL;DR

This paper theoretically investigates valley-selective energy transfer between quantum dots in monolayer transition metal dichalcogenides, emphasizing the role of Coulomb interactions and structural control in exciton dynamics.

Contribution

It introduces a model for resonant energy transfer between localized excitons in quantum dots, accounting for multipole interactions and valley selectivity in 2D semiconductors.

Findings

Valley-selective energy transfer can be structurally controlled.

Multipole interactions significantly influence energy transfer probabilities.

Resonant energy transfer is feasible between neighboring quantum dots.

Abstract

In monolayers of transition metal dichalcogenides the nonlocal nature of the effective dielectric screening leads to large binding energies of excitons. Additional lateral confinement gives rise to exciton localization in quantum dots. By assuming parabolic confinement for both the electron and the hole, we derive model wave functions for the relative and the center-of-mass motions of electron-hole pairs, and investigate theoretically resonant energy transfer among excitons localized in two neighboring quantum dots. We quantify the probability of energy transfer for a direct-gap transition by assuming that the interaction between two quantum dots is described by a Coulomb potential, which allows us to include all relevant multipole terms of the interaction. We demonstrate the structural control of the valley-selective energy transfer between quantum dots.