The vanadium-based kagome superconductor CsV_(3)Sb_(5) has attracted tremendous attention due to its unexcepted anomalous Hall effect(AHE),charge density waves(CDWs),nematicity,and a pseudogap pair density wave(PDW)co...The vanadium-based kagome superconductor CsV_(3)Sb_(5) has attracted tremendous attention due to its unexcepted anomalous Hall effect(AHE),charge density waves(CDWs),nematicity,and a pseudogap pair density wave(PDW)coexisting with unconventional strong-coupling superconductivity.The origins of CDWs,unconventional superconductivity,and their correlation with different electronic states in this kagome system are of great significance,but so far,are still under debate.Chemical doping in the kagome layer provides one of the most direct ways to reveal the intrinsic physics,but remains unexplored.Here,we report,for the first time,the synthesis of Ti-substituted CsV_(3)Sb_(5) single crystals and its rich phase diagram mapping the evolution of intertwining electronic states.The Ti atoms directly substitute for V in the kagome layers.CsV_(3-x)Ti_(x)Sb_(5) shows two distinct superconductivity phases upon substitution.The Ti slightly-substituted phase displays an unconventional V-shaped superconductivity gap,coexisting with weakening CDW,PDW,AHE,and nematicity.The Ti highly-substituted phase has a U-shaped superconductivity gap concomitant with a short-range rotation symmetry breaking CDW,while long-range CDW,twofold symmetry of in-plane resistivity,AHE,and PDW are absent.Furthermore,we also demonstrate the chemical substitution of V atoms with other elements such as Cr and Nb,showing a different modulation on the superconductivity phases and CDWs.These findings open up a way to synthesise a new family of doped CsV_(3)Sb_(5) materials,and further represent a new platform for tuning the different correlated electronic states and superconducting pairing in kagome superconductors.展开更多
A carbon monoxide gas sensor based on single-walled carbon nanotube (SWCNT) has been developed for detection of carbon monoxide (CO) at room temperature. Copper chloride (CuC1) was mixed with SWNT by mechanical ...A carbon monoxide gas sensor based on single-walled carbon nanotube (SWCNT) has been developed for detection of carbon monoxide (CO) at room temperature. Copper chloride (CuC1) was mixed with SWNT by mechanical blending. The thin film was deposited on interdigitated electrodes by using airbrush technology. This paper described the fabrication of the sensor for detecting carbon monoxide with concentrations from 20 ppm to 100 ppm. The performance of CO gas sensor was measured by using relevant apparatus to obtain the continuous sensor electric resistance change on exposure to CO and air atmosphere at room temperature, respectively. The results exhibited that the senor presented a larger sensitivity and a good recoverability. The experimental results suggested the potential use of CuC1 doped SWCNT for CO detecting.展开更多
基金supported by grants from the National Natural Science Foundation of China(61888102,52022105,51771224,11888101,12061131005,and 11834016)the National Key Research and Development Projects of China(2018YFA0305800 and 2019YFA0308500)+6 种基金the Chinese Academy of Sciences(XDB33030100,XDB28010200,and XDB30010000)the Key Research Program of Chinese Academy of Sciences(ZDBS-SSWWHC001)the CAS Project for Young Scientists in Basic Research(YSBR-003)the Beijing Outstanding Young Scientist Program(BJJWZYJH01201914430039)supported by the US DOE,Basic Energy Sciences Grant(DE-FG02-99ER45747)the financial support by the European Research Council(ERC Consolidator Grant,No.815869)the Israel Science Foundation(ISF No.1251/19)。
文摘The vanadium-based kagome superconductor CsV_(3)Sb_(5) has attracted tremendous attention due to its unexcepted anomalous Hall effect(AHE),charge density waves(CDWs),nematicity,and a pseudogap pair density wave(PDW)coexisting with unconventional strong-coupling superconductivity.The origins of CDWs,unconventional superconductivity,and their correlation with different electronic states in this kagome system are of great significance,but so far,are still under debate.Chemical doping in the kagome layer provides one of the most direct ways to reveal the intrinsic physics,but remains unexplored.Here,we report,for the first time,the synthesis of Ti-substituted CsV_(3)Sb_(5) single crystals and its rich phase diagram mapping the evolution of intertwining electronic states.The Ti atoms directly substitute for V in the kagome layers.CsV_(3-x)Ti_(x)Sb_(5) shows two distinct superconductivity phases upon substitution.The Ti slightly-substituted phase displays an unconventional V-shaped superconductivity gap,coexisting with weakening CDW,PDW,AHE,and nematicity.The Ti highly-substituted phase has a U-shaped superconductivity gap concomitant with a short-range rotation symmetry breaking CDW,while long-range CDW,twofold symmetry of in-plane resistivity,AHE,and PDW are absent.Furthermore,we also demonstrate the chemical substitution of V atoms with other elements such as Cr and Nb,showing a different modulation on the superconductivity phases and CDWs.These findings open up a way to synthesise a new family of doped CsV_(3)Sb_(5) materials,and further represent a new platform for tuning the different correlated electronic states and superconducting pairing in kagome superconductors.
基金supported by the National Natural Science Foundation of China(Grant Nos.61176066,61101031)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20120185110012)
文摘A carbon monoxide gas sensor based on single-walled carbon nanotube (SWCNT) has been developed for detection of carbon monoxide (CO) at room temperature. Copper chloride (CuC1) was mixed with SWNT by mechanical blending. The thin film was deposited on interdigitated electrodes by using airbrush technology. This paper described the fabrication of the sensor for detecting carbon monoxide with concentrations from 20 ppm to 100 ppm. The performance of CO gas sensor was measured by using relevant apparatus to obtain the continuous sensor electric resistance change on exposure to CO and air atmosphere at room temperature, respectively. The results exhibited that the senor presented a larger sensitivity and a good recoverability. The experimental results suggested the potential use of CuC1 doped SWCNT for CO detecting.