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Purely one-dimensional bands with a giant spin-orbit splitting: Pb nanoribbons on Si(553) surface

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ABSTRACT

We report on a giant Rashba type splitting of metallic bands observed in one-dimensional structures prepared on a vicinal silicon substrate. A single layer of Pb on Si(553) orders this vicinal surface making perfectly regular distribution of monatomic steps. Although there is only one layer of Pb, the system reveals very strong metallic and purely one-dimensional character, which manifests itself in multiple surface state bands crossing the Fermi level in the direction parallel to the step edges and a small band gap in the perpendicular direction. As shown by spin-polarized photoemission and density functional theory calculations these surface state bands are spin-polarized and completely decoupled from the rest of the system. The experimentally observed spin splitting of 0.6 eV at room temperature is the largest found to now in the silicon-based metallic nanostructures, which makes the considered system a promising candidate for application in spintronic devices.

No MeSH data available.


Results of the SARPES experiments.(a) Spin-averaged photoemission intensity (blue dots) of the bands indicated in Fig. 1(b) together with a fit (red line). The fitted peaks and background are shown as separate curves below experimental data. (b) In-plane (blue) and out-of-plane (red) components of the polarization vector. (c) Direction of the polarization vector of the considered bands. Pz and Px are parallel to the  and  directions, respectively. The number in each diagram denotes corresponding intensity peak (band) shown in (a).
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f4: Results of the SARPES experiments.(a) Spin-averaged photoemission intensity (blue dots) of the bands indicated in Fig. 1(b) together with a fit (red line). The fitted peaks and background are shown as separate curves below experimental data. (b) In-plane (blue) and out-of-plane (red) components of the polarization vector. (c) Direction of the polarization vector of the considered bands. Pz and Px are parallel to the and directions, respectively. The number in each diagram denotes corresponding intensity peak (band) shown in (a).

Mentions: This unusual 1D strongly metallic multi-band structure makes this surface a very unique system. This becomes even more exciting when noticing that the close lying bands crossing the Fermi level resemble the spin-split bands observed in the case of Si(557)-Au and Si(553)-Au surfaces82223. The spin-split bands hypothesis becomes more plausible bearing in mind that Pb atoms feature strong spin-orbit interaction (Zā€‰=ā€‰82) and the low dimensionality of a system can increase this interaction31. In addition, the Rashba-split bands have been observed in a number of Pb structures on different substrates41318323334. Indeed, the spin-resolved ARPES measurements reveal a clear asymmetry between photemission intensity recorded with two channels of the Mott detector. The measurements have been done for the bands indicated by the white line in Fig. 1(b). The spin-averaged photemission intensity distribution of that region is shown in Fig. 4(a) (blue dots) together with the fit (red line) and six peaks (corresponding to six bands), and the background (straight line) used to fit to the experimental data.


Purely one-dimensional bands with a giant spin-orbit splitting: Pb nanoribbons on Si(553) surface
Results of the SARPES experiments.(a) Spin-averaged photoemission intensity (blue dots) of the bands indicated in Fig. 1(b) together with a fit (red line). The fitted peaks and background are shown as separate curves below experimental data. (b) In-plane (blue) and out-of-plane (red) components of the polarization vector. (c) Direction of the polarization vector of the considered bands. Pz and Px are parallel to the  and  directions, respectively. The number in each diagram denotes corresponding intensity peak (band) shown in (a).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382770&req=5

f4: Results of the SARPES experiments.(a) Spin-averaged photoemission intensity (blue dots) of the bands indicated in Fig. 1(b) together with a fit (red line). The fitted peaks and background are shown as separate curves below experimental data. (b) In-plane (blue) and out-of-plane (red) components of the polarization vector. (c) Direction of the polarization vector of the considered bands. Pz and Px are parallel to the and directions, respectively. The number in each diagram denotes corresponding intensity peak (band) shown in (a).
Mentions: This unusual 1D strongly metallic multi-band structure makes this surface a very unique system. This becomes even more exciting when noticing that the close lying bands crossing the Fermi level resemble the spin-split bands observed in the case of Si(557)-Au and Si(553)-Au surfaces82223. The spin-split bands hypothesis becomes more plausible bearing in mind that Pb atoms feature strong spin-orbit interaction (Zā€‰=ā€‰82) and the low dimensionality of a system can increase this interaction31. In addition, the Rashba-split bands have been observed in a number of Pb structures on different substrates41318323334. Indeed, the spin-resolved ARPES measurements reveal a clear asymmetry between photemission intensity recorded with two channels of the Mott detector. The measurements have been done for the bands indicated by the white line in Fig. 1(b). The spin-averaged photemission intensity distribution of that region is shown in Fig. 4(a) (blue dots) together with the fit (red line) and six peaks (corresponding to six bands), and the background (straight line) used to fit to the experimental data.

View Article: PubMed Central - PubMed

ABSTRACT

We report on a giant Rashba type splitting of metallic bands observed in one-dimensional structures prepared on a vicinal silicon substrate. A single layer of Pb on Si(553) orders this vicinal surface making perfectly regular distribution of monatomic steps. Although there is only one layer of Pb, the system reveals very strong metallic and purely one-dimensional character, which manifests itself in multiple surface state bands crossing the Fermi level in the direction parallel to the step edges and a small band gap in the perpendicular direction. As shown by spin-polarized photoemission and density functional theory calculations these surface state bands are spin-polarized and completely decoupled from the rest of the system. The experimentally observed spin splitting of 0.6 eV at room temperature is the largest found to now in the silicon-based metallic nanostructures, which makes the considered system a promising candidate for application in spintronic devices.

No MeSH data available.