A SCANNING-TUNNELING-MICROSCOPY STUDY OF LASER MOLECULAR-BEAM EPITAXY ON SRTIO3(100) SURFACE

We have constructed a new combined system consisting of an ultra-high vacuum scanning tunneling microscope (UHV-STM) and a laser molecular beam epitaxy (laser-MBE) growth chamber with reflection high-energy electron diffraction (RHEED). One of the capabilities of this system was demonstrated by STM imaging of a laser-ablated strontium layer on an atomically flat surface of reduced SrTiO3(100). The surface structure was investigated in real space by atomic-resolution STM and the results were compared with reciprocal space information obtained by RHEED. At room temperature, the STM image showed small Sr islands on the surface which have lateral sizes of 2 to 3 nm with monatomic height. At 320-degrees-C, the Sr atoms were in row structure along the square-root 5 x square-root 5-R26.6-degrees reconstructed surface structure of reduced SrTiO3(100).