Electronic structure of Pr_1−xCa_xMnO₃ from photoemission and inverse photoemission spectroscopies

Abstract

We have studied the occupied and unoccupied electron states of the Pr_1−xCa_xMnO₃ (x=0.2, 0.33 and 0.4) near the Fermi level across their ferromagnetic-antiferromagnetic phase boundary using ultraviolet photoemission spectroscopy and inverse photoemission spectroscopy. The photoemission data show that the pseudogap formation in these compounds occur over an energy scale of 0.48±0.02eV. From a combined analysis of the photoemission and inverse photoemission results, we have estimated the charge transfer energy in these compounds to be ~2.8±0.2eV. The results have been explained on the basis of the theoretical models that describe the electronic phase separation.