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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.


Calculated electronic structure of Si(553)-Pb.Band structure of Si(553)-Pb projected on different rows of Pb atoms.
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f3: Calculated electronic structure of Si(553)-Pb.Band structure of Si(553)-Pb projected on different rows of Pb atoms.

Mentions: The weak contribution of the 6py orbitals can also be observed when the band structure is projected onto individual Pb chains, Fig. 3. Namely, each row of Pb atoms contributes to the band structure located in a different part of the Brillouin zone. The hybridization of these states between neighboring Pb rows is weak, thus one can think of this system as of the set of independent Pb chains rather than Pb nanoribbons. However, some of the bands spread over the whole nanoribbon with varying contribution from different chains. Bands V and VI show such behavior, which indicates that Pb chains are not completely independent. This also is supported by ARPES data, where the Fermi surface shows wavy shapes. On the other hand, a pair of bands I-II and III-IV are localized on particular chains. Thus we deal with two different sets of bands: localized on atomic chains and delocalized. Similar conclusions can be made looking at the charge distribution along the Pb chains for each considered band, Fig. S3.


Purely one-dimensional bands with a giant spin-orbit splitting: Pb nanoribbons on Si(553) surface
Calculated electronic structure of Si(553)-Pb.Band structure of Si(553)-Pb projected on different rows of Pb atoms.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Calculated electronic structure of Si(553)-Pb.Band structure of Si(553)-Pb projected on different rows of Pb atoms.
Mentions: The weak contribution of the 6py orbitals can also be observed when the band structure is projected onto individual Pb chains, Fig. 3. Namely, each row of Pb atoms contributes to the band structure located in a different part of the Brillouin zone. The hybridization of these states between neighboring Pb rows is weak, thus one can think of this system as of the set of independent Pb chains rather than Pb nanoribbons. However, some of the bands spread over the whole nanoribbon with varying contribution from different chains. Bands V and VI show such behavior, which indicates that Pb chains are not completely independent. This also is supported by ARPES data, where the Fermi surface shows wavy shapes. On the other hand, a pair of bands I-II and III-IV are localized on particular chains. Thus we deal with two different sets of bands: localized on atomic chains and delocalized. Similar conclusions can be made looking at the charge distribution along the Pb chains for each considered band, Fig. S3.

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.