Resistance fluctuations in superconducting K_(x)Fe_(2-y)Se_(2) single crystals studied by low-frequency noise spectroscopy

作     者：Hai Zi Yuan Yao Ming-Chong He Di Ke Hong-Xing Zhan Yu-Qing Zhao Hai-Hu Wen Cong Re 子海;姚湲;何明冲;可迪;詹红星;赵宇清;闻海虎;任聪

作者机构：Physics DepartmentSchool of Physics and AstronomyYunnan UniversityKunming 50500China Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of ScienceBeijing 100190China Physics DepartmentNanjing UniversityNanjing 210093China 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2021年第30卷第4期

页      面：502-507页

核心收录：

学科分类：080705[工学-制冷及低温工程] 07[理学] 070205[理学-凝聚态物理] 08[工学] 0807[工学-动力工程及工程热物理] 0702[理学-物理学] 

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.11774303 and 11574373) Joint Fund of Yunnan Provincial Science and Technology Department,China(Grant No.2019FY003008) 

主　　题：K_(x)Fe_(2-y)Se_(2) phase separation noise and chaos percolation 

摘      要：Low-frequency resistance noise spectroscopy is applied to investigate bulk single crystals of the intercalated ironselenide K_(x)Fe_(2-y)Se_(2) superconductors with different iron vacancy *** on a generalized fluctuation model,the well-observed resistance hump above 100 K is interpreted as an insulator-metal phase transition with a characteristic transition energy of 0.1-0.6 eV,indicating a highly inhomogeneous energy distribution *** the superconducting transition regime,we find that the normalized resistance noise scales with resistance R excellently as S_(R)/R^(2)∝R^(l_(rs)) with the noise exponent lrs≈*** reduced iron vacancy disordering in enhanced superconductivity K_(x)Fe_(2-y)Se_(2) crystals,the level of resistance fluctuations is greatly suppressed,suggesting a geometrical phase transition for conduction channel,which is directly related to the microstructure of the crystals.