By Peter Weiss
Most substances expand when warmed. That can be bad, especially in devices such as precision telescopes, whose components must maintain their shapes across a wide temperature range. Now, scientists have discovered a metallic compound that nixes thermal expansion by what appears to be an unprecedented mechanism.
Mercouri G. Kanatzidis and his colleagues at Michigan State University in East Lansing created the compound by heating a mixture of equal parts of ytterbium, gallium, and germanium to 850C and then cooling the melt to room temperature.