Mostofi Group

Spotlight

• 

  Chemical control of negative thermal expansion

  Most materials expand when they are heated, but a few do the opposite as a result of certain kinds of atomic vibrations. In this work, which appears on the cover of JACS, the layered perovskite Ca_3–xSr_xMn₂O₇ is shown to exhibit a switching from a material exhibiting uniaxial negative to positive thermal expansion as a function of x.