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Polarons in two-dimensional polar materials: All-coupling variational theory

A. Kudlis1,*, V. Shahnazaryan2,†, and I. V. Tokatly3,4,5,‡

  • *Contact author: andrewkudlis@gmail.com
  • †Contact author: vanikshahnazaryan@gmail.com
  • ‡Contact author: ilya.tokatly@ehu.es
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Phys. Rev. Research 8, 013050 – Published 20 January, 2026

DOI: https://doi.org/10.1103/dv7k-5jjz

Abstract

We present a detailed and self-contained theoretical study of polarons in two-dimensional (2D) polar materials, which extends the classical macroscopic theory of Fröhlich polarons to the 2D case. The theory is fully determined by experimentally accessible parameters, the static and optical 2D polarizabilities of a monolayer, the frequency of transverse optical phonons, and the effective mass of charge carriers. We define a single dimensionless parameter, which characterizes the coupling of electrons with longitudinal optical phonons, analyze both weak- and strong-coupling regimes, and adapt the Feynman variational path-integral approach for a high-quality interpolation between these limits. Our results provide insight into the ground-state energy and effective mass of polarons in modern 2D polar monolayers.

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Phys. Rev. Research 8, 013050– Published 20 January, 2026
  • Received 23 July 2025
  • Accepted 3 December 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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