Pulsed laser deposition-grown SrVO3 (001) ultrathin films on SrTiO3 (001) substrates were investigated by in situ low-temperature scanning tunneling microscopy and spectroscopy. SrVO3 (001) ultrathin films showed two distinct surface terminations. One termination was a (√2 ×√2)-R45° reconstruction as was previously observed for SrVO3 (001) thick films, while the other was a (√5 ×√5)-R26.6° reconstruction. Scanning tunneling spectroscopy revealed that the (√2 ×√2)-R45° surface shows a metallic electronic structure, whereas the (√5×√5)-R26.6° surface exhibits a significantly reduced density of states at the Fermi level. These results suggest that the surface reconstruction may be an important factor to influence metallicity in epitaxial ultrathin films of transition metal oxides.
References
A domain boundary can be seen in the upper part of Fig. 2(b).
