Investigations of the Surface Electric Structure of the Rashba Semiconductors BiTeBr by Fourier-Transform Scanning Tunneling Microscopy
Date Issued
2015
Date
2015
Author(s)
Lien, Yen-Neng
Abstract
In this work, we combined the results of scanning tunneling microscopic, spectroscopic and the Fourier-transform scanning tunneling microscopic (also called ’quasi- particle analysis’), and the chemistry and electronic structure known from the published literatures to investigate the Rashba semiconductor BiTeBr. In the literatures, there are two kinds of crystal structure of BiTeBr, and only one of them, the ordered one has the Rashba type spin-splitting. According to our scanning tunneling microscopy topography images and comparing with the scanning tunneling spectroscopy result, two uniform polar terminations on scales exceeding 1 mm with an unit cell height difference. If the surface is positively polarized, it is the Te termination, which accompanies with the induced band bending forms an accumulation layer confining Rashba spin-splitting electrons on it. In this accumulation layer of Te-terminated surface, we observed the standing wave of the Bloch wavefunctions forms quasiparticle interference patterns, which is scattered around the surface defects. Energy and q-value dispersion relation observation shows a linear electron-like dispersion which indicates the band electrons dispersion relation of energy and wavevector. This investigation provide us more understanding of semiconductor with relativistic and strongly spin-orbit of a Rashba type spin-splitting material by the STM. But calculation results are still needed to compare with.
Subjects
scanning tunneling microscopy
Rashba effect
quasi-particle interference
polar surface
BiTeBr
Type
thesis