Mn/PbTe(111) interface behavior studied by photoemission

We performed X-ray photoemission spectroscopy (XPS) investigation on the interface behavior at the Mn/PbTe(111) interface. The measurement shows the drastic changes at atomic level and the Mn/PbTe (111) interface formation. Upon Mn deposition, a new peak component associated with metallic Pb appears in the Pb core-level at low binding energies, and a new peak component related to MnTe compound appears in the Te core-level at high binding energies. These new features become more and more obvious in XPS spectra with increasing Mn thickness, and at the Mn thickness higher than 7 ML (beyond the escape depths of Pb and Te), the substrate features disappear. Upon further deposition of Mn, the intensity of the metallic Pb core level keeps constant, while the intensity of Te 3d core level of MnTe compound decreases with increasing Mn thickness, and finally the Te 3d core level disappears at Mn thickness of about 102 ML. Based oil these results, we can conclude that, upon Mn depostion, both Te and Pb segregate to the surface region, the segregated Pb as metallic Pb floats on the top of Mn overlayer, and the segregated Te is bound in the Mn overlayer as MnTe.