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  • Letter
  • Open Access

Coulomb-mediated interactions of charge-transfer excitons in TMD lateral heterostructures

Kabyashree Sonowal*, Daniel Erkensten, Ermin Malic, and Roberto Rosati

  • Department of Physics, Philipps-Universität Marburg, 35037 Marburg, Germany and mar.quest—Marburg Center for Quantum Materials and Sustainable Technologies, 35032 Marburg, Germany

  • *Contact author: kavyashrees06@gmail.com
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Phys. Rev. B 114, L171407 – Published 23 September, 2026

DOI: https://doi.org/10.1103/wm33-yhyl

Abstract

Lateral heterostructures of transition-metal dichalcogenides (TMDs) host spatially separated charge-transfer (CT) excitons. While analogous to interlayer excitons in vertical TMD heterostructures, these interfacial excitons possess much larger in-plane dipoles of several nanometers and an additional center-of-mass quantization. Here, we investigate mutual interactions between these highly dipolar CT excitons using a quantum mechanical approach. Accounting for the dipolar and quantum exchange interactions, we evaluate the experimentally accessible density-dependent energy renormalization and predict a net energy blueshift of a few meV for bound CT excitons. Interestingly, for small dipole moments, the energy renormalization displays a quadratic dependence with respect to the dipole moment, in contrast to the linear dependence found in vertical TMD heterostructures. We show that spatial energy offset and temperature are the key tuning knobs for controlling the density-dependent excitonic response. Overall, our results contribute to a better microscopic understanding of CT excitons and their interactions in lateral TMD heterostructures.

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Phys. Rev. B 114, L171407– Published 23 September, 2026
  • Received 3 June 2026
  • Revised 27 August 2026
  • Accepted 31 August 2026
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