Interface behavior of Mn/PbTe(111) studied by scanning tunneling microscopy and X-ray photoemission spectroscopy

Abstract

Mn overlayers growth on PbTe(111) have been investigated by using scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS). The strong chemical interactions were found during the formation of Mn/PbTe(111) interface. At the initial deposition of Mn, one part of Mn adatoms substitute Pb atoms on the PbTe(111) surface, forming a (√3 × √3)R30° MnTe phase, and the other part of Mn adatoms, together with the kicked-out Pb atoms, nucleate at the boundaries of the MnTe islands, forming loop islands around the MnTe islands as an intermediate state. Finally, they develop into regular 3D Pb capped Mn islands upon further Mn deposition. For Mn growth on the PbTe surface where Pb atoms are almost completely substituted by Mn, the deposited Mn atoms either cooperate into the 3D Pb capped Mn islands promoting the upright growth of the 3D Pb capped Mn islands, or nucleate and grow on the MnTe superstructure areas. Free Pb layer always floats on the top of surface, indicating that Pb layer has smaller surface energy, and Mn adatoms always exchange the positions with the underneath Pb atoms during the growth.