Viscosity of finite Yukawa liquids

The shear viscosity of a finite two-dimensional (2D) Yukawa liquid is calculated using non-equilibrium Langevin simulations. Two counter-propagating shear forces are used to push the particles and cause shear-induced melting of the cluster. The melting temperature of the 2D cluster system is used to derive the effective coupling parameter Γ * of this finite system and allows us to investigate the relationship between shear viscosity and system properties Γ * and κ. The simulation data shows that the value of the shear viscosity rises for coupling parameters Γ * > 20 and follows a simple universal scaling for appropriate normalization. It is further found that the Green–Kubo relation is applicable to determine viscosity in finite non-equilibrium systems with Γ * < 80.