Fermi Surface and Band Structure of（Ca,La）FeAs₂ Superconductor from Angle-Resolved Photoemission Spectroscopy

【摘要】 The（Ca,R）FeAs₂（R=La,Pr,etc.）superconductors with a signature of superconductivity transition above40 K possess a new kind of block layers that consist of zig-zag As chains.We report the electronic structure of the new（Ca,La）FeAs₂ superconductor investigated by both band structure calculations and high resolution angle-resolved photoemission spectroscopy measurements.Band structure calculations indicate that there are four hole-like bands around the zone centerΓ（0,0）and two electron-like bands near the zone corner M（π,π）in CaFeAs₂.In our angle-resolved photoemission measurements on(Ca_0.9La_0.1)FeAs₂,we have observed three holelike bands around theΓpoint and one electron-like Fermi surface near the M（π,π）point.These results provide important information to compare and contrast with the electronic structure of other iron-based compounds in understanding the superconductivity mechanism in the iron-based superconductors.更多还原

【Abstract】 The（Ca,R）FeAs₂（R=La,Pr,etc.） superconductors with a signature of superconductivity transition above40 K possess a new kind of block layers that consist of zig-zag As chains.We report the electronic structure of the new（Ca,La）FeAs2 superconductor investigated by both band structure calculations and high resolution angle-resolved photoemission spectroscopy measurements.Band structure calculations indicate that there are four hole-like bands around the zone center r（0,0） and two electron-like bands near the zone corner M（π,π） in CaFeAs2.In our angle-resolved photoemission measurements on(Ca_0.9La_0.1)FeAs2,we have observed three holelike bands around the Γ point and one electron-like Fermi surface near the M（π,π） point.These results provide important information to compare and contrast with the electronic structure of other iron-based compounds in understanding the superconductivity mechanism in the iron-based superconductors.更多还原