Abstract
In this work, we studied a few surfaces, of which the structures have not yet been revealed, using reflection high-energy positron diffraction (RHEPD). We studied the Ge(111)/Pb and Ge(111)/Sn surfaces that exhibit the phase transition from 3×3 to √3×√3 periodicities at around 200K. We found that in both phases the equilibrium positions of Pb and Sn adatoms are conserved. That is, in the unit-cell, one of three adatoms is located upper position and two of them are located lower positions (one-up-two-down). The phase transition is interpreted in terms of an order-disorder type. We furthermore studied the quasi-one dimensional Si(111)/In surface which exhibits the metal-insulator transition at around 120K. The high temperature phase is well explained as the zigzag chain structure. We found that a dynamic atomic displacement which leads to the formation of hexagon structure occur below 120 K. We confirmed the appearance of the band gap using the surface structure determined from the RHEPD rocking curves.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.