Metal-Semiconductor Transition Concomitant with a Structural Transformation in Tetrahedrite Cu^sub 12^Sb^sub 4^S^sub 13

• Published in: Journal of the Physical Society of Japan 2016-01, Vol.85 (1), p.1
• Main Authors: Tanaka, Hiromi I, Suekuni, Koichiro, Umeo, Kazunori, Nagasaki, Toshiki, Sato, Hitoshi, Kutluk, Galif, Nishibori, Eiji, Kasai, Hidetaka, Takabatake, Toshiro
• Format: Article
• Language: English
• Subjects: Diffraction; Ions; Phase transitions; Pressure; Semiconductors; Spectrum analysis
• ISSN: 0031-9015; 1347-4073

The tetrahedrite ... undergoes a metal-semiconductor transition (MST) at ... = 85 K, whose mechanism remains elusive. Our Cu 2p X-ray photoemission spectroscopy study revealed the monovalent state of Cu ions occupying the two sites in this compound. This fact excludes the possibilities of previously proposed antiferromagnetic order and Jahn-Teller instability inherent in a divalent Cu system. A synchrotron X-ray diffraction study has revealed that the body-centered cubic cell of ... transforms into a body-centered 2a x 2a x 2c tetragonal supercell below ..., where the cell volume per formula unit expands by 0.25%. We have further studied pressure effects on the MST as well as the effects of the substitution of As for Sb. The application of pressure above 1 GPa completely inhibits the MST and leads to a metallic state, suggesting that the low-temperature structure with a larger volume becomes unstable under pressure. The As substitution also reduces the volume and suppresses the MST but the full substitution induces another transition at 124 K. (ProQuest: ... denotes formulae/symbols omitted.)