Broken Symmetry (IMAGE) Brown University Caption Researchers used tiny beads arranged in a crystalline lattice to investigate how two-dimensional solids melt. The research examined the effects of interstitial defects -- extra particles in a crystalline structure. They found that while one interstitial made little different, two interstitials broke the symmetry of the lattice. The findings help explain why 2-d solids melt before theories predict they should Credit Ling Lab/Brown University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.