Comparison of the measured electronic structure of the colossal magnetoresistive manganites and high T-c superconductors: Band structure, photoemission lineshapes, and a pseudogap

We have used high energy-resolution angle-resolved photoemission spectrosco py to study the k-dependent electronic structure of single-crystalline samp les of the manganese-based perovskites as a function of doping level, tempe rature, and layer number. An especially important aspect of the data is a t emperature and sample-type dependent pseudogap which drastically depletes t he spectral weight at E-F. In contrast to the pseudogap observed in the hig h T-c superconductors, the pseudogap in the manganites is essentially isotr opic in k-space, implying that a local effect such as a lattice distortion should be responsible. (C) 1998 Elsevier Science Ltd. All rights reserved.