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O: Fachverband Oberflächenphysik
O 75: Metal Substrates: Growth Studies
O 75.1: Vortrag
Mittwoch, 18. März 2020, 15:00–15:15, WIL C107
Growth studies of the potential Rashba surface alloy Tl on Ag(111) — •Patrick Härtl and Matthias Bode — Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
It is well known, that surface alloys of Ag(111) with heavy post-transition metals,
such as the group V element Bi or the group IV element Pb,
i.e., BiAg2 [1] or PbAg2 [2], respectively,
exhibit a giant spin–orbit coupling resulting in Rashba spin-split surface states.
Looking in the periodic system it can be speculated whether surface alloying of Ag
with the group III element thallium (Tl) results in a comparable electronic structure.
As a first step towards this goal we have studied the growth of Tl on Ag(111) by low-energy electron diffraction (LEED),
Auger electron spectroscopy (AES), and scanning tunneling microscopy (STM).
LEED reveals a (√3 × √3)Tl/Ag(111)R30∘ structure at submonolayer coverage
and additional (4 √3 × 4 √3) spots for thicker films.
The intensity and sharpness of the (√3 × √3) is used to identify optimal growth conditions.
The LEED results are compared to real space data by making use of Fourier transformed STM images.
STM data obtained on Tl films with a thickness of several atomic layers still show a pronounced moiré pattern,
thereby indicating a sizable rotation of the Tl lattice with respect to the underlying Ag(111) substrate.
The results will be discussed by comparison with Bi and Pb films.
[1] L. El-Kareh et al.,
Phys. Rev. Lett. 110, 176803 (2013).
[2] L. El-Kareh et al.,
New Jour. Phys. 16, 045017 (2014).