| 09:00-10:40 | Tu1: Transport in electronic devices |
| 10:40-11:20 | Coffee break |
| 11:20-13:00 | Tu2: Surface diffusion and migration |
| 13:00-15:30 | Lunch break (on your own) |
| 15:30-16:40 | Tu3: Chemistry and growth of graphene |
| 16:40-17:20 | Coffee break |
| 17:20-18:50 | Tu4: Electron-phonon coupling in graphene |
| 19:00-21:30 | Poster session A |
Chair: J. Manson, Clemson, USA
Contributed talk
Investigation of surface structure and diffusion dynamics of hydrogen adsorbed on Sb(111)
Institute of Experimental Physics, Graz University of Technology, Graz, Austria
As one of the essential components in the class of topological insulators [1] (TI), the semimetal antimony (Sb) and its surfaces has received growing attention by experimental groups throughout the last years. Despite experimental advances in ultra-high-vacuum (UHV) technologies, experimental studies on pure material surfaces may still suffer from the ever-present hydrogen background in vacuum chambers. Moreover, thin layers of hydrogen are more or less invisible to electron scattering methods. Since adsorbed hydrogen atoms on the surface may alter the electronic response of the material, detecting the presence of hydrogen on the surface of a TI is of major importance.
Helium atom scattering (HAS) provides a completely surface sensitive method of materials characterization and can thus provide information on the structure and electronic properties of the very first layer of the sample material [2,3,4].
HAS experiments were performed on cold Sb(111) surfaces without and with coverage of hydrogen molecules or atoms. While the presence of H2 did not alter the surface diffraction spectrum compared to an uncovered surface, atomic hydrogen coverage resulted in a complete loss of diffraction peaks at low surface temperature. By raising the temperature, the diffraction pattern was regained. However, heating up to a temperature of 500 K was required in order to obtain the clean surface spectrum.
HAS experimental data of the surface temperature dependent diffraction patterns of ordered hydrogen on Sb(111) as well as a determination of its diffusion energy barrier will be presented.
[1] H. Zhang et al., Nature Physics 5,438-442 (2009)
[2] M. Mayrhofer-R. et al., J. Phys. Condens. Matter 25, 395002 (2013)
[3] M. Mayrhofer-R. et al., Phys. Rev. B 88, 205425 (2013)
[4] P. Kraus et al., Phys. Rev. B 87, 245433 (2013)