Anisotropic scattering of surface state electrons at a point defect on Bi(111)

Abstract

Scanning tunneling microscopy was applied to study the lateral variation of the local density of electronic states on the Bi(111) surface in the vicinity of a point defect. At an energy close to the Fermi level a characteristic pattern with a threefold symmetry is found. The pattern can be attributed to the scattering between two electronic surface states which are split by spin orbit coupling. The observation is well described by the superposition of three monochromatic waves. The phase of the waves relative to the center of the defect leads to a reduction to a threefold symmetry.

Barrier-free subsurface incorporation of3dmetal atoms into Bi(111) films

“…In contrast to Refs. [7,8], where morphological features such as Bi adatoms or clusters cause comparable scattering patterns, we do not observe any feature in the center of the Co-induced pattern. The pattern resembles, however, those in Bi 2 Te 3 (111) films where Fe atoms occupy substitutional Bi sites [20].…”

“…Besides bismuth chalcogenides such as Bi 2 Se 3 and Bi 2 Te 3 , also Bi bulk is a well-known model system for materials with strongly spin-split surface states [1][2][3][4][5][6]. Application of these novel material systems, however, requires the controlled tuning of properties such as band gap, carrier density, or doping level by electronic or morphological manipulation [7][8][9][10][11]. Often the electron transport in 2D surface electron systems is strongly influenced by individual scatterers, e.g., single atoms or molecules [7,8,12].…”

“…Often the electron transport in 2D surface electron systems is strongly influenced by individual scatterers, e.g., single atoms or molecules [7,8,12]. Unintentional defects such as step edges or impurities frequently show pronounced scattering patterns in scanning tunneling microscopy (STM) [7,[13][14][15][16][17][18][19]. In contrast to these uncontrolled surface modifications, the deposition of single atoms at the surface, usually followed by thermally activated in-diffusion, allows for intentional doping of the near-surface region.…”

“…Application of these novel material systems, however, requires the controlled tuning of properties such as band gap, carrier density, or doping level by electronic or morphological manipulation [7][8][9][10][11]. Often the electron transport in 2D surface electron systems is strongly influenced by individual scatterers, e.g., single atoms or molecules [7,8,12]. Unintentional defects such as step edges or impurities frequently show pronounced scattering patterns in scanning tunneling microscopy (STM) [7,[13][14][15][16][17][18][19].…”

Diffusing magnetic Tb impurities and magnetotransport in strongly spin-polarized Bi films

“…Among others, Bi turned out to be a valuable prototype system to study the interplay between the electronic band structure and propagating electrons in these surface states. [3][4][5][6][7][8][9] In this respect, epitaxial Bi(111) films were shown to be attractive study objects, since the bulk states become gapped due to robust confinement. Thus the surface states can be probed directly by transport measurements.…”