In December 2024, the world first stand-alone Low Energy high intensity heave ion Accelerator Facility(LEAF) has been commissioned to its design performance and passed the acceptance test conducted by theNational Natu...In December 2024, the world first stand-alone Low Energy high intensity heave ion Accelerator Facility(LEAF) has been commissioned to its design performance and passed the acceptance test conducted by theNational Natural Science Foundation of China. LEAF is designed and built by the Institute of Modern Physics,CAS, which is aiming to provide unprecedent ion beam conditions for the researches of nuclear astrophysics,atomic physics, nuclear materials and so on. To realize this goal, it is essential to develop an ECR (ElectronCyclotron Resonance) ion source beyond the performance of the state-of-the-art machines. This ECR ionsource is called FECR (First 4th generation ECR ion source) designed to be operated with the plasma heatedby 45 GHz microwave frequency that needs high magnetic field confinement. Therefore, with FECR Nb_(3)Snsuperconducting technology was incorporated to ECR ion source for the first time in the world. FECR featuresNb_(3)Sn solenoids and NbTi sextupole coils that enables its high performing operation at 45 + 28 GHz microwaveheating.展开更多
Fe-based superconductors represent a fascinating class of materials,extensively studied for their complex interplay of superconductivity,magnetism,spin density waves,and nematicity,along with the interactions among th...Fe-based superconductors represent a fascinating class of materials,extensively studied for their complex interplay of superconductivity,magnetism,spin density waves,and nematicity,along with the interactions among these orders.An intriguing yet unexplained phenomenon observed in Fe-based superconductors is the emergence of superconductivity below 25K in the non-superconducting parent compound SrFe_(2)As_(2)following exposure to water at its surface.In this study,we employed in situ angle-resolved photoemission spectroscopy and low-energy electron diffraction to meticulously examine the electronic structure evolution of SrFe_(2)As_(2)upon in situ water dosing.Our findings indicate that water dosing markedly attenuates the spin density wave phase and surface Sr reconstruction while preserving the nematic order in SrFe_(2)As_(2).Furthermore,we detected an enhancement in the spectral weight of bands near the Fermi level.Our observations highlight the critical role of the intricate interplay among various orders induced by water dosing,which effectively modifies the band structure and favors the emergence of superconductivity in SrFe_(2)As_(2).展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11427904,12025506)the Scientific Instrument Developing Project of the Chinese Academy of Sciences,Grant No.GJJSTD20210007.
文摘In December 2024, the world first stand-alone Low Energy high intensity heave ion Accelerator Facility(LEAF) has been commissioned to its design performance and passed the acceptance test conducted by theNational Natural Science Foundation of China. LEAF is designed and built by the Institute of Modern Physics,CAS, which is aiming to provide unprecedent ion beam conditions for the researches of nuclear astrophysics,atomic physics, nuclear materials and so on. To realize this goal, it is essential to develop an ECR (ElectronCyclotron Resonance) ion source beyond the performance of the state-of-the-art machines. This ECR ionsource is called FECR (First 4th generation ECR ion source) designed to be operated with the plasma heatedby 45 GHz microwave frequency that needs high magnetic field confinement. Therefore, with FECR Nb_(3)Snsuperconducting technology was incorporated to ECR ion source for the first time in the world. FECR featuresNb_(3)Sn solenoids and NbTi sextupole coils that enables its high performing operation at 45 + 28 GHz microwaveheating.
基金supported by the National Nature Science Foundation of China[Grant Nos.92365204 and 12274298(Z.K.Liu)]the National Key R&D program of China[Grant No.2022YFA1604400/03(Z.K.Liu)]Zhangjiang Laboratory(Y.M.Zhang).The authors thank BL02B at the Shanghai Synchrotron Radiation Facility supported by the National Natural Science Foundation of China(Contract No.11227902).
文摘Fe-based superconductors represent a fascinating class of materials,extensively studied for their complex interplay of superconductivity,magnetism,spin density waves,and nematicity,along with the interactions among these orders.An intriguing yet unexplained phenomenon observed in Fe-based superconductors is the emergence of superconductivity below 25K in the non-superconducting parent compound SrFe_(2)As_(2)following exposure to water at its surface.In this study,we employed in situ angle-resolved photoemission spectroscopy and low-energy electron diffraction to meticulously examine the electronic structure evolution of SrFe_(2)As_(2)upon in situ water dosing.Our findings indicate that water dosing markedly attenuates the spin density wave phase and surface Sr reconstruction while preserving the nematic order in SrFe_(2)As_(2).Furthermore,we detected an enhancement in the spectral weight of bands near the Fermi level.Our observations highlight the critical role of the intricate interplay among various orders induced by water dosing,which effectively modifies the band structure and favors the emergence of superconductivity in SrFe_(2)As_(2).
