Observation of Strain and Temperature Induced Changes in the Band Structure of Thin La$_{0.8}$MnO$_{3-\delta }$ films

Mn K-edge resonant inelastic x-ray scattering measurements were performed on ultrathin and thick films of La$_{0.8}$MnO$_{3-\delta }$,. The measurements reveal that strain causes large shifts of the Mn 3d and Mn 4p/4s bands above the Fermi level. While the thick films track the behavior of bulk samples, the thinnest film is found to exhibit a switch from a localized 3d band at high temperature to a delocalized metal band at low temperature. The strain induced switching behavior opens the possibility of tuning the transition to higher temperatures for device applications in this class of manganite materials.