In-situ angle-resolved photoemission study of MBE-grown (La, Ce)2CuO4 thin films

We have performed in-situ angle-resolved photoemission spectroscopy on the electron doped cuprate superconductor La2-xCexCuO4 (x = 0.1) using high-quality films grown by molecular beam epitaxy. The obtained photoemission spectra were free from dirt peaks. In addition, the time evolution of the spectra due to impurity adsorption is rather gradual, and the sample surface is stable even at ambient temperature, which is in contrast with previous reports on bulk Nd2-xCexCuO4 (NCCO) single crystals. The energy distribution curves show clear dispersions near the Fermi energy (EF) with some EF crossings. The resultant Fermi surface is hole-like and centered around (pi, pi), which essentially agrees with that predicted for NCCO by band calculations and also with the experimentally determined Fermi surface of optimally doped NCCO (x = 0.15).