STRUCTURAL AND ELECTRONIC-PROPERTIES OF LIQUID TELLURIUM

By contrast with liquid Se, liquid Te shows metallic behavior. It is widely accepted that metallic Te has a threefold-coordinated network structure. However, recent neutron diffraction data suggest that a twofold-coordinated chain structure subsists in liquid Te and Se. Besides, 'Why does liquid Te show metallic behavior?' is one of the long-standing problems in the field of liquid metals. The structural and electronic properties of liquid Te and small droplets of Te supercooled to 240-degrees-C have been investigated by means of EXAFS. neutron diffraction, optical reflectivity and magnetic susceptibility measurements. The data reveal that the twofold chain of liquid Te is composed of shorter and longer covalent bonds. The fraction of shorter bonds increases with decreasing temperature. The Te chain tends to have a stacked planar zigzag geometry, which is similar to the high-pressure metallic crystal. The metallic nature of liquid Te arises from the broadening of lone pairs bands along the stacked direction.