Solid–liquid transition induced by rigidity disparity in a binary mixture of cell tissues

Abstract

The two-dimensional melting of a binary mixture of cell tissues is numerically investigated in the presence of rigidity disparity. We present the full melting phase diagrams of the system by using the Voronoi-based cellular model. It is found that the enhancement of rigidity disparity can induce a solid–liquid transition at both zero temperature and finite temperature. (i) In the case of zero temperature, the system undergoes a continuous solid–hexatic transition followed by a continuous hexatic–liquid transition for zero rigidity disparity, but a discontinuous hexatic–liquid transition for finite rigidity disparity. Remarkably, the solid–hexatic transitions always arise when the soft cells reach the rigidity transition point of monodisperse systems. (ii) In the case of finite temperature, the melting occurs via a continuous solid–hexatic transition followed by a discontinuous hexatic–liquid transition. Our study may contribute to the understanding of solid–liquid transitions in binary mixture systems with rigidity disparity.