The electronic structure of La_1−xSr_xMnO₃ thin films and its T_c dependence as studied using angle-resolved photoemission

We present angle-resolved photoemission spectroscopy (ARPES) results for thin films of the three-dimensional manganese perovskite La1-xSrxMnO3. We show that the temperature of the transition (T-c) from the paramagnetic insulating to the ferromagnetic metallic state is closely related to details of the electronic structure, particularly to the spectral weight at the k-point, where the sharpest step at the Fermi level was observed. We found that this k-point is the same for all the samples, despite their different values of Tc. The change of Tc is discussed in terms of kinetic energy optimization. Our ARPES results suggest that the change of the electronic structure for the samples having different transition temperatures is different from the rigid band shift.