Elastic properties of fcc phases of soft polydisperse spheres, interacting through inverse-power pair potentials , where r is the distance between sphere centers, have been studied by Monte Carlo (MC) simulations in the NpT ensemble with variable shape of the box. The simulations show that both the size polydispersity and temperature T strongly influence the elastic properties of the studied system, including Poisson's ratio. Poisson's ratio is found to be negative and decreases with increase of temperature and size polydispersity in the direction. Hence, the system is partially auxetic. Additionally, the obtained results indicate that wide range of Poisson's ratio values (from to ) can be obtained by changing the polydispersity, the potential softness and direction.
Poisson's ratio in and directions for polydisperse soft spheres with and dimensionless pressure versus dimensionless temperature.