Correlation between superconductivity and antiferromagnetism in Rb sub(0.8)Fe sub(2-y)Se sub(2-x)Te sub(x) single crystals

• Published in: Physical review. B, Condensed matter and materials physics Vol. 85; no. 17
• Main Authors: Gu, Dachun, Sun, Liling, Wu, Qi, Zhang, Chao, Guo, Jing, Gao, Peiwen, Wu, Yue, Dong, Xiaoli, Dai, Xi, Zhao, Zhongxlin
• Format: Journal Article
• Language: English
• Published: 01-05-2012
• Subjects: Antiferromagnetism; Condensed matter; Electrical resistance; Lattices; Semiconductors; Single crystals; Superconductivity; Transition temperature
• ISSN: 1098-0121; 1550-235X

We report experimental evidence for the connection between superconductivity and antiferromagnetism in Rb sub(0.8)Fe sub(2-y)Se sub(2-x)Te sub(x) single crystals under negative chemical pressure introduced by the lattice expansion of substituting Se with isovalent Te atoms. Electrical resistance and magnetic measurements in the temperature range from 4 to 600 K demonstrate that both superconducting transition temperature (T sub(c)) and the Neel temperature (T sub(N)) are suppressed continuously with the lattice expansion. When the Te concentration x in Rb sub(0.8)Fe sub(2-y)Se sub(2-x)Te sub(x) approaches 0.4, the superconductivity is completely suppressed, and the sample behaves like a semiconductor; meanwhile, the features for antiferromagnetic transition on resistance and magnetization curves disappear. Our observation suggests that the effect of negative-pressure-induced lattice expansion can be used to tune the correlativity of superconductivity and antiferromagnetism in the studied system.