Electronic structure of bulk metallic glass Zr₅₅Al ₁₀Cu₃₀Ni₅

The electronic structure of a bulk metallic glass Zr₅₅Al ₁₀Cu₃₀Ni₅ has been studied by means of photoelectron spectroscopy in order to understand the origins of its large glass formation ability and unique mechanical properties from the microscopic point of view. The valence-band photoelectron spectra show three bands ascribed to the Zr 4d, Ni 3d, and Cu 3d states. A remarkable feature of these bands is the highly symmetric spectral shape with the high-binding energy and narrow width in comparison with the d bands of the crystalline transition metals. This is attributed to the lack of the crystalline periodicity in the metallic glass as well as the reduction in the neighbouring atoms to hybridize with those transition metals. A high-resolution valence-band spectrum also reveals the intensity reduction near the Fermi level, which implies that the pseudo-gap in the electronic structure may be one of the important factors for the glass formation.