University of Arizona researchers claim a little "doping," or the introduction of a different type of atom, will solve the problem and let hot nanoscale materials retain their size and shape. U of A researchers computer modeled material with copper atoms, then introduced an antimony atom to see the effect. The simulated antimony atom moved through the material to settle at the grain boundary, the place where one layer of copper atoms ends and another begins. Having an atom of a different size from the main material changes the distance between the atoms. This appears to be the key to keeping things together when temperature changes.