We report comprehensive angle-resolved photoemission investigations on the electronic structures and nematicity of the parent compounds of the iron-based superconductors including CeFeAsO, BaFe2As2, NaFeAs, FeSe and u...We report comprehensive angle-resolved photoemission investigations on the electronic structures and nematicity of the parent compounds of the iron-based superconductors including CeFeAsO, BaFe2As2, NaFeAs, FeSe and undoped FeSe/SrTiO3 films with 1, 2 and 20 layers. While the electronic structure near tile Brillouin zone center F varies dramatically among different materials, the electronic structure near the Brillouin zone corners （M points）, as well as their temperature dependence, are rather similar. The electronic structure near the zone corners is dominated by the electronic nematicity that gives rise to a band splitting of the dxz and dyz bands below the nematie transition temperature. A clear relation is observed between the band splitting magnitude arid the onset temperature of nematicity. Our results may shed light on the origin of nematicity, its effect on the electronic structures, and its relation with superconductivity in the iron-based superconductors.展开更多
采用超高效液相色谱-四极杆-飞行时间串联质谱(ultra-high performance liquid chromatography coupled with quadrupole/time-of-flight tandem mass spectrometry,UPLC-Q/TOF-MS/MS)技术,对夏佛塔苷口服给药后在小鼠体内的原形成分及...采用超高效液相色谱-四极杆-飞行时间串联质谱(ultra-high performance liquid chromatography coupled with quadrupole/time-of-flight tandem mass spectrometry,UPLC-Q/TOF-MS/MS)技术,对夏佛塔苷口服给药后在小鼠体内的原形成分及其代谢产物进行定性分析。动物福利和实验过程获得徐州医科大学伦理委员会的批准(批准号:XZMULL201612024)。通过分析各成分的精确分子质量、一级、二级质谱信息,并与相应的对照品及文献比对,从小鼠血浆、胆汁、尿液和粪便中共鉴定出1个原形成分和29个代谢产物。这些成分在小鼠体内代谢的主要途径有去羟基化、羟基化、脱糖化、糖化、氢化、甲基化、乙酰化、硫酸化、葡糖醛酸化等。研究结果可为进一步阐明夏佛塔苷的药效物质基础提供有价值的依据。展开更多
The development of Eu-based chalcogenides with exceptional nonlinear optical(NLO)performance in the infrared(IR)region has garnered increasing attention.However,the design and synthesis of such compounds with non-cent...The development of Eu-based chalcogenides with exceptional nonlinear optical(NLO)performance in the infrared(IR)region has garnered increasing attention.However,the design and synthesis of such compounds with non-centrosymmetric(NCS)structures remain a significant challenge.In this study,we report the successful synthesis of a novel quaternary Eu-based chalcogenide,β-EuZnGeS_(4),achieved through an isovalent cation substitution strategy starting from the ternary parent compound Eu_(2)GeS_(4).This innovative approach induces a structural transformation from centrosymmetric to non-centrosymmetric,thereby enhancing the NLO properties.β-EuZnGeS_(4)crystallizes in the orthorhombic Fdd2 space group,with a unique two-dimensional[ZnGeS_(4)]^(2−) layer structure that accommodates Eu^(2+)cations.Notably,β-EuZnGeS_(4) exhibits a well-balanced set of optical properties,including a remarkable phasematching second-harmonic generation(SHG)effect,with its maximum SHG value being twice that of AgGaS_(2) with a 2050 nm laser.Additionally,it exhibits a high laser-induced damage threshold,surpassing AgGaS_(2) by a factor of 13.1,along with a broad transparency window extending from 0.39 to 23.7μm.Theoretical calculations further reveal that these outstanding optical properties stem from the synergistic effects of the highly distorted tetrahedral[ZnS_(4)]and[GeS_(4)]motifs within the crystal lattice.This work not only expands the materials database for rare-earth metal chalcogenides but also provides a novel strategy for designing NCS structures with tailored optical properties for a wide range of applications.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11190022,11334010 and 11534007the National Basic Research Program of China under Grant No 2015CB921000the Strategic Priority Research Program(B)of Chinese Academy of Sciences under Grant No XDB07020300
文摘We report comprehensive angle-resolved photoemission investigations on the electronic structures and nematicity of the parent compounds of the iron-based superconductors including CeFeAsO, BaFe2As2, NaFeAs, FeSe and undoped FeSe/SrTiO3 films with 1, 2 and 20 layers. While the electronic structure near tile Brillouin zone center F varies dramatically among different materials, the electronic structure near the Brillouin zone corners （M points）, as well as their temperature dependence, are rather similar. The electronic structure near the zone corners is dominated by the electronic nematicity that gives rise to a band splitting of the dxz and dyz bands below the nematie transition temperature. A clear relation is observed between the band splitting magnitude arid the onset temperature of nematicity. Our results may shed light on the origin of nematicity, its effect on the electronic structures, and its relation with superconductivity in the iron-based superconductors.
文摘采用超高效液相色谱-四极杆-飞行时间串联质谱(ultra-high performance liquid chromatography coupled with quadrupole/time-of-flight tandem mass spectrometry,UPLC-Q/TOF-MS/MS)技术,对夏佛塔苷口服给药后在小鼠体内的原形成分及其代谢产物进行定性分析。动物福利和实验过程获得徐州医科大学伦理委员会的批准(批准号:XZMULL201612024)。通过分析各成分的精确分子质量、一级、二级质谱信息,并与相应的对照品及文献比对,从小鼠血浆、胆汁、尿液和粪便中共鉴定出1个原形成分和29个代谢产物。这些成分在小鼠体内代谢的主要途径有去羟基化、羟基化、脱糖化、糖化、氢化、甲基化、乙酰化、硫酸化、葡糖醛酸化等。研究结果可为进一步阐明夏佛塔苷的药效物质基础提供有价值的依据。
基金supported by the National Natural Science Foundation of China(22175175)Natural Science Foundation of Fujian Province(2022L3092 and 2023H0041)+1 种基金Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR118)the Youth Innovation Promotion Association CAS(2022303).
文摘The development of Eu-based chalcogenides with exceptional nonlinear optical(NLO)performance in the infrared(IR)region has garnered increasing attention.However,the design and synthesis of such compounds with non-centrosymmetric(NCS)structures remain a significant challenge.In this study,we report the successful synthesis of a novel quaternary Eu-based chalcogenide,β-EuZnGeS_(4),achieved through an isovalent cation substitution strategy starting from the ternary parent compound Eu_(2)GeS_(4).This innovative approach induces a structural transformation from centrosymmetric to non-centrosymmetric,thereby enhancing the NLO properties.β-EuZnGeS_(4)crystallizes in the orthorhombic Fdd2 space group,with a unique two-dimensional[ZnGeS_(4)]^(2−) layer structure that accommodates Eu^(2+)cations.Notably,β-EuZnGeS_(4) exhibits a well-balanced set of optical properties,including a remarkable phasematching second-harmonic generation(SHG)effect,with its maximum SHG value being twice that of AgGaS_(2) with a 2050 nm laser.Additionally,it exhibits a high laser-induced damage threshold,surpassing AgGaS_(2) by a factor of 13.1,along with a broad transparency window extending from 0.39 to 23.7μm.Theoretical calculations further reveal that these outstanding optical properties stem from the synergistic effects of the highly distorted tetrahedral[ZnS_(4)]and[GeS_(4)]motifs within the crystal lattice.This work not only expands the materials database for rare-earth metal chalcogenides but also provides a novel strategy for designing NCS structures with tailored optical properties for a wide range of applications.
