arXiv subjects

E. A. Gaiduk

Publications and source records attributed to E. A. Gaiduk.

3 recordsLinked to original sources

arXiv2021

A new mechanism of structural transition in 2D Hertzian spheres in the presence of random pinning

Using molecular dynamics simulation we have investigated the influence of random pinning on the phase diagram and melting scenarios of a two-dimensional (2D) system with the Hertz potential for $α=5/2$. For the first time it has been shown that random pinning can cardinally change the mechanism of first-order transition between the different crystalline phases (triangular and square) by virtue of generating hexatic and tetratic phases: a triangular crystal to hexatic transition is of the continuous Berezinskii-Kosterlitz-Thouless (BKT) type, a hexatic to tetratic transition is of the first-order, and finally, a continuous BKT type transition from tetratic to the square crystal.

cond-mat.soft↗

arXiv2019

The influence of random pinning on the melting scenario of two-dimensional soft-disk systems

We present the results of a computer simulation study of the melting scenario of two-dimensional soft-disk systems with potential $U(r)=\varepsilon(σ/r)^n$, $n=12$ and $n=1024$, both in the presence of random pinning and without it. The melting parameters have been determined from analysis of the behavior of equations of state, correlation functions of the orientational and translational order parameters, Young modulus and renormalization group equations. The transition points obtained from these criteria are in good agreement. We have shown that the systems melted in two stages - first-order hexatic phase to liquid transition and the continuous Berezinskii-Kosterlitz-Thouless type crystal-hexatic phase transition. Random pinning widened the hexatic phase, but left the melting scenario unchanged.

cond-mat.soft↗

arXiv2018

Phase diagram and melting scenarios of two-dimensional Hertzian spheres

We present computer simulations of a system of purely repulsive soft colloidal particles interacting via the Hertz potential and constrained to a two-dimensional plane. This potential describes the elastic interaction of weakly deformable bodies and can be a reliable model for qualitative description of behavior of soft macromolecules, like globular micelles and star polymers. We find a large number of ordered phases, including the dodecagonal quasicrystal, and analyze the melting scenarios of low density triangle and square phases. It is interesting that depending on the position on the phase diagram the system can melt both through the first order transition and in accordance with the Berezinskii-Kosterlitz-Thouless-Halperin-Nelson-Young (BKTHNY) scenario (two continuous transitions with the intermediate hexatic phase) and also in accordance with recently proposed two-stage melting with the first order hexatic-isotropic liquid transition and continuous solid-hexatic transition. We also demonstrate the possibility of the tricritical point on the melting line.

cond-mat.soft↗