Influence of k broadening on ARPES spectra of the (110) and (001) surfaces of SrVO 3 films INFLUENCE of k BROADENING on ARPES ⋯ T. MITSUHASHI et al.

To examine the effect of k broadening on angle-resolved photoemission spectroscopy (ARPES) spectra, in situ ARPES using the variable polarization of synchrotron light has been performed for the (110) and (001) surfaces of SrVO3 films. Using the polarization dependence for the band structures of the V 3dt2g states, we have separately observed the dxy-derived states and the dyz/dzx ones for the (110) surface. It is found that ARPES images for the dyz/dzx states are considerably broader than those for the dxy states. Meanwhile, such a broadening is not observed in the identical dyz/dzx-derived band dispersion along the crystallographically equivalent direction on the (001) surface, indicating that the broadening of the ARPES image originates from the absence or presence of mirror symmetry in the respective states with respect to the ARPES-measurement planes. The observed spectroscopic behavior is well reproduced by the simulation where the k broadening in the photoelectron emission process is taken into account. These results indicate that the consideration of the mirror symmetry of the band structures with respect to the ARPES-measurement plane is important for analyzing the ARPES-spectral line shape in the case that the k-broadening effect is dominant in ARPES spectra.