Unexpected electronic properties of strained La/sub 1.85/Sr/sub 0.15/CuO/sub 4/ epitaxial films

Surprising results on electronic properties of strained thin La/sub 1.85/Sr/sub 0.15/CuO/sub 4/ epitaxial films are reported. We report on the very first angle resolved photoemission (ARPES) measurements of the dispersion on in-situ grown, in-plane compressed T-phase LSCO films (showing T/sub C/ enhancement). The data show clear band crossing, implying that in-plane compressive strain at constant doping results in the suppression of the saddle point, changing the topology of the Fermi surface from hole-like to electron-like.