Random pinning elucidates the nature of melting transition in two-dimensional core-softened potential system

Abstract

Despite about forty years of investigations, the nature of the melting transition in two dimensions is not completely clear. In the framework of the most popular Berezinskii-Kosterlitz-Thouless-Halperin-Nelson-Young (BKTHNY) theory, 2D systems melt through two continuous Berezinskii-Kosterlitz-Thouless (BKT) transitions with intermediate hexatic phase. The conventional first-order transition is also possible. On the other hand, recently on the basis of computer simulations the new melting scenario was proposed with continuous BKT type solid-hexatic transition and first order hexatic-liquid transition. However, in the simulations the hexatic phase is extremely narrow that makes its study difficult. In the present paper, we propose to apply the random pinning to investigate the hexatic phase in more detail. The results of molecular dynamics simulations of two dimensional system having core-softened potentials with narrow repulsive step which is similar to the soft disk system are outlined. The system has a small fraction of pinned particles giving quenched disorder. Random pinning widens the hexatic phase without changing the melting scenario and gives the possibility to study the behavior of the diffusivity and order parameters in the vicinity of the melting transition and inside the hexatic phase.

7 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1608.05232

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Cited by in corpus (7)

• Phase diagram and melting scenarios of two-dimensional Hertzian spheres
• Waterlike anomalies in a 2D core-softened potential
• The role of attraction in the phase diagrams and melting scenarios of generalized 2D Lennard-Jones systems
• The influence of random pinning on the melting scenario of two-dimensional soft-disk systems
• A new mechanism of structural transition in 2D Hertzian spheres in the presence of random pinning
• Signatures of two-step impurity mediated vortex lattice melting in Bose-Einstein Condensates
• Controlling Vortex Lattice Structure of Binary Bose-Einstein Condensates via Disorder Induced Vortex Pinning