Dynamics of glass surfaces by STM

Glasses have been used for thousands of years, covering a wide range of applications from daily appliances to optical, electronic and medical devices. However, the microscopic understanding of glasses and the glass transition remains a highly active and controversial area. In addition to the bulk glass, studying surface glass dynamics likely contributes equally towards understanding the connection between theories of glass and experiments to test these theories.

We study surface glassy dynamics by making Scanning Tunneling Microscopy(STM) movies of various amorphous surfaces including metallic glasses, amorphous silicon, amorphous silicon carbide and amorphous hafnium diboride. Surface glassy dynamics under external stress including temperature and light irradiation is also investigated. In addition to STM under UHV, AFM is employed to investigate amorphous silicon dioxide surface under water.

D. Nguyen, L. Nienhaus, R. T. Haasch, J. Lyding and M. Gruebele, “Sub-nanometer glass surface dynamics induced by illumination”, J. Chem. Phys.,142, 234505 (2015).