Electronic Structure Reconstruction Of Ca1-Xprxfe2as2 In The Collapsed Tetragonal Phase

We report the electronic structure reconstruction of Ca1-xPrxFe2As2 in the low temperature collapsed tetragonal (CT) phase observed by angle-resolved photoemission spectroscopy. Different from Ca(Fe1-xRhx)(2)As-2 and the annealed CaFe2As2 where all hole Fermi surfaces are absent in their CT phases, the cylindrical hole Fermi surface still persists in the CT phase of Ca1-xPrxFe2As2. Furthermore, we found at least three well separated electronlike bands around the zone corner in the CT phase of Ca1-xPrxFe2As2, which are more dispersive than the electronlike bands in the high temperature tetragonal phase. Based on these observations, we propose that the weakening of correlations (as indicated by the reduced effective mass), rather than the lack of Fermi surface nesting, might be responsible for the absence of magnetic ordering and superconductivity in the CT phase.