The Poisson ratio of crystalline surfaces
  A remarkable theoretical prediction for a crystalline (polymerized) surface is that its Poisson ratio (\sigma) is negative. Using a large scale Monte Carlo simulation of a simple model of such surfaces we show that this is indeed true. The precise numerical value we find is (\sigma \simeq -0.32) on a (128^2) lattice at bending rigidity (kappa = 1.1). This is in excellent agreement with the prediction (\sigma = -1/3) following from the self-consistent screening approximation of Le Doussal and Radzihovsky. 
Marco Falcioni (Syracuse U.), Mark Bowick (Syracuse U.), Emmanuel   Guitter (Saclay) and Gudmar Thorleifsson (Bielefeld)