Manipulation of Glassy State in Amorphous Selenium by Low-temperature Internal Friction Measurements

We have studied the thickness and quench-rate dependent internal friction of amorphous selenium (a-Se) thin films deposited at room temperature. The internal friction of a-Se films exhibit a temperature independent plateau below 1 K followed by a broad maximum at 10 K. The plateau, which is seen in almost all amorphous solids, is caused by dissipation by two-level tunneling systems (TLS), whose origin is still unknown. The maximum is caused by thermal relaxation over the same energy barrier that induces TLS. The internal friction and shear modulus are almost thickness independent from 100 nm t...