Sensing surface states of Bi films by magnetotransport

Lükermann, Daniel; Sologub, S.V.; Pfnür, H.; Tegenkamp, Christoph

doi:10.1103/physrevb.83.245425

Cited by 30 publications

(47 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Details about the fabrication of the contacts and the in situ cleaning procedures of the Si samples are described elsewhere. 7,17 Bi has been evaporated out of a ceramic crucible, while Tb has been evaporated by direct current heating of a tantalum stripe to which a small piece of pure Tb has been attached by spot welding. The quality and crystallinity of the Si surface and Bi films have been checked by low-energy electron diffraction (LEED).…”

Section: Methodsmentioning

confidence: 99%

“…Monocrystalline films with average grain sizes in the order of 10 nm are routinely obtained by adsorption of Bi at 200 K followed by annealing to 450 K for several minutes. 7,14 Figure 1(a) shows a typical LEED-pattern of a 20 bilayer (BL, 1 BL = 1.14 × 10 15 atoms/cm 2 ) thick Bi(111) film (here we use the rhombohedral notation for indexing the Bi planes, 18 i.e., the surface normal coincides with the [111] direction). The faint ring structure is to a small rotational disorder of the (111)-textured domains.…”

Section: Methodsmentioning

confidence: 99%

“…7 Therefore electronic transport is limited by scattering at surface defects in this temperature range. This is the reason why we describe here a detailed analysis of the surface morphology of the Bi films.…”

Section: A Structure and Roughness Of Pristine Bi(111) Filmsmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

“…Thus the surface states can be probed directly by transport measurements. 7,10 The surfaces of such semimetallic thin-film systems exhibit strong similarities with topological insulators (TI). Therefore they can be used to study related questions without dealing with stoichiometry problems or adsorbate-induced gaps of the topological surface states.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

et al. 2013

View full text Add to dashboard Cite

As a contribution to electronic transport within strongly spin-polarized surface states and its modification by adsorption of magnetic impurities we studied the adsorption of Tb (atomic magnetic moment 10 μ B ) on epitaxial Bi(111) films by means of surface sensitive (magneto)conductance and low-energy electron diffraction. Surface diffusion turned out to be non-negligible even at substrate temperatures of 10 K. The Tb adatoms finally nucleate at intrinsic defects of the Bi (111) surface, where the Tb impurities act as dopants but not as scatterers. Nevertheless, time-dependent measurements allowed to determine also single-particle Tb scattering properties, as also supported by simulations of adsorption kinetics and time-dependent conductance. The magnetoconductance properties are characterized by small charge transfer (0.05 e/atom) and strong spin-orbit scattering, which in this case results only in strong reduction of the weak antilocalization effect but not a reversal to weak localization as for Fe and Co [see Lükermann, Sologub, Pfnür, Klein, Horn-von Hoegen, and Tegenkamp, Phys. Rev. B 86, 195432 (2012)]. Although Tb has a magnetic moment, which is by far higher than for adsorbed Fe and Co, it turns out that the f electrons of Tb play essentially no role in scattering of the conduction electrons, yielding an even smaller scattering cross section than that for Fe and Co. The adatom coordination (interstitial or on the surface) may also play an important role.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: A Structure and Roughness Of Pristine Bi(111) Filmsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

et al. 2013

View full text Add to dashboard Cite

show abstract

Effect of adsorbed magnetic and non‐magnetic atoms on electronic transport through surfaces with strong spin‐orbit coupling

Lükermann

Sologub²,

Pfnür

et al. 2013

Materialwissenschaft Werkst

View full text Add to dashboard Cite

Adsorption‐induced reduction of the surface state conductivity in epitaxial Bi(111) films, a prototype system with a large Rashba‐induced surface state splitting by adsorbed atoms of Bi, Fe and Co was investigated by macroscopic surface magneto‐transport measurements at a temperature of 10 K. A detailed analysis of magneto‐transport, DC‐transport and Hall data reveals that the scattering efficiencies for Co and Fe are by a factor of two larger than for Bi. While for the latter, charge transfer and change of band filling near the Fermi level is negligible, we found an increase of hole concentration upon Co and Fe adsorption. These atoms act as acceptors and retract roughly 0.5 electrons from the surface per adsorbed atom. Besides the dominant classical magneto‐conductance signal the films show signatures of weak anti‐localization (WAL) reflecting the strong spin‐orbit coupling in Bi(111) surface states. Our measurements show that the control of hybridization is important in order to make use of local spin‐moments and to increase the backscattering rate in strongly spin‐orbit coupled systems, e. g., topological insulators.

show abstract

The dominance of surfaces and interfaces: A view to magnetoconductance and structure in low‐dimensional crystalline films

Pfnür

Lükermann

Tegenkamp

2012

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

For ultra-thin films, electronic transport properties at surfaces and interfaces are dominated by electronic scattering at the interfaces. Therefore, as our example with Pb on Si(557) shows, d.c. transport is sensitive to confinement, to growth modes, and to (electronic) surface roughness. During the growth of Pb on Si(557) up to more than 10 monolayers, we found classical and quantum size effects, a pronounced conductance anisotropy and conductance oscillations directly related to the anisotropic layer-by-layer growth mode of the Pb film on this regularly stepped surface. In fact, it turned out that the interface anisotropy, which extends up to the seventh layer in conductance, is kept as a memory effect even for thick (isotropic) layers. By adding a magnetic field, details of the scattering mechanism at impurities and defects are revealed, since elastic, inelastic, spin-orbit scattering contributions can be separated.Strong changes of scattering properties are evident when going from the multilayers to the monolayer, as demonstrated again for the system Pb on Si(557). Contrary to multilayers, spinorbit scattering dominates for the monolayer, presumably due to the symmetry reduction at the surface and the appearance of spin-split bands split by the Rashba effect. Also the anomaly in spin-orbit scattering close to monolayer completion, coupled with quasi one-dimensional d.c. conductance, can be ascribed to the Rashba effect. The intriguing interplay between bulk and surface conductance with large Rashba split states at the surface is exemplified by a study of multilayer growth of Bi on Si(111). By magnetoconductance we were able to separate bulk from surface contributions. Scattering between strongly spinpolarized Rashba-split states spin can be effectively suppressed, so that only the ''classical'' magnetoconductance effect remains, as observed in this system.

show abstract

Sensing surface states of Bi films by magnetotransport

Cited by 30 publications

References 21 publications

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

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

Effect of adsorbed magnetic and non‐magnetic atoms on electronic transport through surfaces with strong spin‐orbit coupling

The dominance of surfaces and interfaces: A view to magnetoconductance and structure in low‐dimensional crystalline films

Contact Info

Product

Resources

About