Showing papers by "Jun Chen published in 1991"
TL;DR: In this paper, near-edge X-ray absorption spectroscopy measurements of Bi and Tl L3-edges and Cu K-edge in a series of compounds were presented.
Abstract: Near-edge X-ray absorption spectroscopy measurements of Bi and Tl L3-edges and Cu K-edge in a series of compounds Tl 1− x Bi x Sr 2 CuO 5 and Tl 0.5 Bi 0.5 Sr 2 CaCu 2 O 7 have been presented. The results provides strong evidence for the existence of mixed-valent Bi and Tl in these compounds. Moreover, the formal valence of copper in Tl 1− x Bi x Sr 2 CuO 5 and Tl 0.5 Bi 0.5 Sr 2 CaCu 2 O 7 appears to be much higher than 2+. It is suggested that the Tl(Bi) 6s band could cross the Fermi level, resulting in electronic correlations between the Tl(Bi)-O and Cu-O layers, which is significant in determining the physical properties of these compounds.
17 citations