Two-Dimensional Melting: From Liquid-Hexatic Coexistence to Continuous Transitions
Двумерное плавление: от сосуществования жидкости и гексатика до непрерывных переходов
2015-01-22
SCID: 54.1/9xsfmrv6
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Debye-Hückel screening lengthKTHNY scenarioYukawa particlesevent-chain Monte Carlohexatic-solid transitionliquid-hexatic coexistencerepulsive power-law interactionssoft diskstwo-dimensional melting
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Abstract (AI)
The phase diagram of two-dimensional continuous particle systems is studied using the event-chain Monte Carlo algorithm. For soft disks with repulsive power-law interactions ∝r^{-n} with n≳6, the recently established hard-disk melting scenario (n→∞) holds: a first-order liquid-hexatic and a continuous hexatic-solid transition are identified. Close to n=6, the coexisting liquid exhibits very long orientational correlations, and positional correlations in the hexatic are extremely short. For n≲6, the liquid-hexatic transition is continuous, with correlations consistent with the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) scenario. To illustrate the generality of these results, we demonstrate that Yukawa particles likewise may follow either the KTHNY or the hard-disk melting scenario, depending on the Debye-Hückel screening length as well as on the temperature.
Key Findings
1
For n ≲ 6 the liquid-hexatic transition becomes continuous, with correlations consistent with the KTHNY (Kosterlitz-Thouless-Halperin-Nelson-Young) scenario.
2
For soft disks with repulsive power-law interactions ∝ r^{-n}, the hard-disk melting scenario holds for n ≳ 6: a first-order liquid-hexatic coexistence and a continuous hexatic-solid transition are observed.
3
Near n = 6, the coexisting liquid shows very long orientational correlations while the hexatic phase displays extremely short positional correlations.
4
Yukawa interacting particles can follow either the KTHNY scenario or the hard-disk melting scenario depending on Debye-Hückel screening length and temperature, demonstrating the generality of the results.
Research Object
Two-dimensional continuous particle systems with repulsive interactions (soft disks with r^{-n} power-law and Yukawa particles)
Research Subject
Melting phase behaviour: nature of the liquid–hexatic and hexatic–solid transitions (first-order versus continuous), correlation lengths and agreement with hard-disk or KTHNY melting scenarios as a function of interaction exponent n, Debye–Hückel screening length, and temperature
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2015-01-22
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