High-resolution angle-resolved photoemission spectroscopy study of the electronic structure of EuFe2As2

摘要

We report the high-resolution angle-resolved photoemission spectroscopystudies of electronic structure of EuFe2As2. The paramagnetic state data arefound to be consistent with density-functional calculations. In theantiferromagnetic ordering state of Fe, our results show that the bandsplitting, folding, and hybridization evolve with temperature, which cannot beexplained by a simple folding picture. Detailed measurements reveal that a tinyelectron Fermi pocket and a tiny hole pocket are formed near (pi,pi) in the(0,0)-(pi,pi) direction, which qualitatively agree with the results of quantumoscillations, considering kz variation of Fermi surface. Furthermore, nonoticeable change within the energy resolution is observed across theantiferromagnetic transition of Eu2+ ordering, suggesting weak coupling betweenEu sublattice and FeAs sublattice.