The relationship between charge-density-wave(CDW) and superconductivity(SC), two vital physical phases in condensed matter physics, has always been the focus of scientists’ research over the past decades. Motivated b...The relationship between charge-density-wave(CDW) and superconductivity(SC), two vital physical phases in condensed matter physics, has always been the focus of scientists’ research over the past decades. Motivated by this research hotspot, we systematically studied the physical properties of the layered telluride chalcogenide superconductors CuIr_(2-x)Al_(x)Te_(4)(0 ≤x≤ 0.2). Through the resistance and magnetization measurements, we found that the CDW order was destroyed by a small amount of Al doping. Meanwhile, the superconducting transition temperature(T_(c)) kept changing with the change of doping amount and rose towards the maximum value of 2.75 K when x = 0.075. The value of normalized specific heat jump(△C/γT_(c)) for the highest T_(c) sample CuIr_(2-x)Al_(x)Te_(4)was 1.53, which was larger than the BCS value of 1.43 and showed the bulk superconducting nature. In order to clearly show the relationship between SC and CDW states,we propose a phase diagram of T_(c) vs. doping content.展开更多
The iron-chalcogenide high temperature superconductor Fe(Se,Te)(FST) has been reported to exhibit complex magnetic ordering and nontrivial band topology which may lead to novel superconducting phenomena. However, the ...The iron-chalcogenide high temperature superconductor Fe(Se,Te)(FST) has been reported to exhibit complex magnetic ordering and nontrivial band topology which may lead to novel superconducting phenomena. However, the recent studies have so far been largely concentrated on its band and spin structures while its mesoscopic electronic and magnetic response, crucial for future device applications, has not been explored experimentally. Here, we used scanning superconducting quantum interference device microscopy for its sensitivity to both local diamagnetic susceptibility and current distribution in order to image the superfluid density and supercurrent in FST. We found that in FST with 10% interstitial Fe,whose magnetic structure was heavily disrupted, bulk superconductivity was significantly suppressed whereas edge still preserved strong superconducting diamagnetism. The edge dominantly carried supercurrent despite of a very long magnetic penetration depth. The temperature dependences of the superfluid density and supercurrent distribution were distinctively different between the edge and the bulk.Our Heisenberg modeling showed that magnetic dopants stabilize anti-ferromagnetic spin correlation along the edge, which may contribute towards its robust superconductivity. Our observations hold implication for FST as potential platforms for topological quantum computation and superconducting spintronics.展开更多
基金the financial support by the National Natural Science Foundation of China (Grant No. 11922415)Guangdong Basic and Applied Basic Research Foundation, China (Grants No. 2019A1515011718)+8 种基金the Pearl River Scholarship Program of Guangdong Province Universities and Colleges (Grants No. 20191001)supported by the National Natural Science Foundation of China (Grants No. 11974432)the National Key R&D Program of China (Grant Nos. 2018YFA0306001 and 2017YFA0206203)the financial support by the National Key Laboratory Development Fund (No. 20190030)partial support by the National Key R&D Program of China (Grant No. 2017YFA0303000)National Natural Science Foundation of China (Grant No. 11827805)Shanghai Municipal Science and Technology Major Project, China (Grant No. 2019SHZDZX01)supported by the National Natural Science Foundation of China (Grant Nos. 11904414 and 12174454)the National Key R&D Program of China (Grant No. 2019YFA0705702)。
文摘The relationship between charge-density-wave(CDW) and superconductivity(SC), two vital physical phases in condensed matter physics, has always been the focus of scientists’ research over the past decades. Motivated by this research hotspot, we systematically studied the physical properties of the layered telluride chalcogenide superconductors CuIr_(2-x)Al_(x)Te_(4)(0 ≤x≤ 0.2). Through the resistance and magnetization measurements, we found that the CDW order was destroyed by a small amount of Al doping. Meanwhile, the superconducting transition temperature(T_(c)) kept changing with the change of doping amount and rose towards the maximum value of 2.75 K when x = 0.075. The value of normalized specific heat jump(△C/γT_(c)) for the highest T_(c) sample CuIr_(2-x)Al_(x)Te_(4)was 1.53, which was larger than the BCS value of 1.43 and showed the bulk superconducting nature. In order to clearly show the relationship between SC and CDW states,we propose a phase diagram of T_(c) vs. doping content.
基金Yihua Wang would like to acknowledge partial support by the Ministry of Science and Technology of China(2016YFA0301002 and 2017YFA0303000)the National Natural Science Foundation of China(11827805)+4 种基金Shanghai Municipal Science and Technology Major Project Da Jiang would like to acknowledge partial support by the‘‘Strategic Priority Research Program(B)”of the Chinese Academy of Sciences(XDB04040300)the National Natural Science Foundation of China(11274333)Hundred Talents Program of the Chinese Academy of Sciences.Shaoyu Yin would like to acknowledge support by the National Natural Science Foundation of China(11704072)Work at Stanford was supported by an NSF IMR-MIP(DMR-0957616)part of the National Nanotechnology Coordinated Infrastructure under award ECCS-1542152.
文摘The iron-chalcogenide high temperature superconductor Fe(Se,Te)(FST) has been reported to exhibit complex magnetic ordering and nontrivial band topology which may lead to novel superconducting phenomena. However, the recent studies have so far been largely concentrated on its band and spin structures while its mesoscopic electronic and magnetic response, crucial for future device applications, has not been explored experimentally. Here, we used scanning superconducting quantum interference device microscopy for its sensitivity to both local diamagnetic susceptibility and current distribution in order to image the superfluid density and supercurrent in FST. We found that in FST with 10% interstitial Fe,whose magnetic structure was heavily disrupted, bulk superconductivity was significantly suppressed whereas edge still preserved strong superconducting diamagnetism. The edge dominantly carried supercurrent despite of a very long magnetic penetration depth. The temperature dependences of the superfluid density and supercurrent distribution were distinctively different between the edge and the bulk.Our Heisenberg modeling showed that magnetic dopants stabilize anti-ferromagnetic spin correlation along the edge, which may contribute towards its robust superconductivity. Our observations hold implication for FST as potential platforms for topological quantum computation and superconducting spintronics.
