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Interaction-range-controlled crossover from first-order to continuous melting in two-dimensional diplon crystals

Paulo S. Branicio*

  • *Contact author: branicio@usc.edu
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APS Open Sci. 1, 000117 – Published 31 August, 2026

DOI: https://doi.org/10.1103/r36h-bzv9

Abstract

Molecular dynamics simulations of two-dimensional (2D) diplon crystals (electrons on helium films) reveal a melting crossover from first order to continuous as film thickness d grows relative to lattice constant a. At small d/a, hysteresis persists at N=40000 alongside a strong Binder-cumulant anomaly. At large d/a, hysteresis vanishes and orientational correlations decay algebraically with η6=0.31±0.04, near the Kosterlitz-Thouless-Halperin-Nelson-Young bound of 1/4, consistent with continuous melting within the investigated system sizes and numerical resolution; disclination unbinding limits any hexatic phase to ΔT/Tm<0.5%. The diplon system thus tunes 2D melting, relevant to electrons-on-helium quantum computing.

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Outline

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APS Open Sci. 1, 000117– Published 31 August, 2026
Vol. 1
  • Received 5 May 2026
  • Accepted 19 August 2026
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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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