Correlation between boson peak and thermal expansion manifested by physical aging and high pressure

We investigate the effects of high pressure and physical aging on the boson peak and thermal expansion of a typical metallic glass. Specifically, the thermal expansion coefficient and boson peak intensity monotonically decrease during physical aging. With the increase of high pressure, the boson peak intensity and the thermal expansion coefficient coincidently experience an incipient decrease and then a subsequent increase. The boson peak intensity shows an approximately linear relationship with the thermal expansion coefficient. The thermal expansion can be affected by structural relaxation or rejuvenation, which can reflect the flow units variation and atomic packing of a metallic glass. Our results indicate a direct link between structural relaxation or rejuvenation and fast boson peak dynamics, providing insights into the boson peak behavior and structural heterogeneity of metallic glasses. metallic glass, thermal expansion, boson peak, high pressure, aging PACS number(s): 61.43.Dq, 61.20.Lc, 62.50.+p, 61.72.Cc, 65.60.+a