Ultrastable glasses behave differently at low temperature

Glasses are usually described as disordered solids, but not all glasses are equally disordered. Ultrastable glasses, prepared by vapour deposition, can have much lower energy and a more ordered local structure than ordinary glasses. Their behaviour provides a test of ideas about what makes a glass stable.

At very low temperatures, most amorphous solids show quantum tunnelling states, which affect their heat capacity and other properties. The study found that ultrastable indomethacin glasses are a surprising exception: the tunnelling states that would normally be expected are suppressed.

The result was published in the Proceedings of the National Academy of Sciences. It is relevant to the centre's wider interest in the stability and behaviour of materials, including thin films and nanostructured systems.