We propose an experimental approach to extract separately the surface and interface phase shift of standing waves in metallic quantum well (QW) structures composed of isostructural perovskite oxides. The “asymmetric” vacuum/SrVO${}_3$/SrTiO${}_3$ and “symmetric” SrTiO${}_3$/SrVO${}_3$/SrTiO${}_3$ QW structures are fabricated in an epitaxial multilayer form. Using these metallic QW structures, the phase shifts at the surface (vacuum/SrVO${}_3$) and interface (SrTiO${}_3$/SrVO${}_3$) are successfully obtained by analyzing a thickness series of angle-resolved photoemission spectra. The difference of the phase shift between the two boundaries reveals that nearly ideal quantum confinement is achieved at the interface, indicating that a SrTiO${}_3$ layer acts as a useful potential barrier.

• Received 17 June 2013

DOI:https://doi.org/10.1103/PhysRevB.88.115308