An efficient route for fabricating regular and spatially-dense nanostructure arrays over a large area is to exploit self-organization of adsorbates on a substrate featuring a periodic pattern at the nanoscale. One such possibility is the engineering of one-dimensional (1D) quantum structures on stepped surfaces of silicon. Metal adsorbates act to stabilize flat and stepped (vicinal) Si(111) surfaces, leading to reconstructions having 1D features that are also interesting from a fundamental perspective. The exact structural and electronic properties of these monatomic wires depends on several factors, including the step width [1] and step morphology [2], the presence of adatoms [3], and spin-orbit coupling [3]. For instance, in the case of the prototypical Si(111)-(5x2)-Au surface reconstruction, adatoms appear to induce a spontaneous period doubling that is accompanied by an unusual `double' Peierls mechanism. A recent study [4] of 1-D indium chains on Si(111) demonstrated that low energy, anisotropic optical transitions probed by RAS are particularly sensitive probes of 1D behaviour, possibly because the largest 1D exotic effects are expected to be seen near the Fermi level. We present a joint experimental-theoretical study of the structural, electronic and optical properties of nominal and vicinal reconstructed Si(111)-Au surfaces, and interpret the measured reflectance anisotropy spectroscopy (RAS) data of these systems [5]. A phenomenological interpretation of the observed spectra has previously been proposed, but ab initio approaches are necessary for a thorough understanding of the structure and optical response. The role of adatoms, spin-orbit coupling, and higher order effects in the optical response will be addressed[6]. [1] F. Himpsel et al, J. Phys.: Cond. Mat 13, 11097 (2001). [2] N. McAlinden and J. F. McGilp, Euro. Phys. Letters 92, 67008 (2010). [3] S. Erwin et al, Phys. Rev. B 80, 155409 (2009). [4] S. Chandola et al, Phys. Rev. Lett. 102, 226805 (2009). [5] N. McAlinden and J. F. McGilp, J. Phys. Condens. Matter 21, 474208 (2009). [6] C. Hogan, N. McAlinden, and J. F. McGilp, Phys. Status Solidi, accepted (2012)
Optical characterization of Au nanowires on Si(111) surfaces
Conor Hogan;
2012
Abstract
An efficient route for fabricating regular and spatially-dense nanostructure arrays over a large area is to exploit self-organization of adsorbates on a substrate featuring a periodic pattern at the nanoscale. One such possibility is the engineering of one-dimensional (1D) quantum structures on stepped surfaces of silicon. Metal adsorbates act to stabilize flat and stepped (vicinal) Si(111) surfaces, leading to reconstructions having 1D features that are also interesting from a fundamental perspective. The exact structural and electronic properties of these monatomic wires depends on several factors, including the step width [1] and step morphology [2], the presence of adatoms [3], and spin-orbit coupling [3]. For instance, in the case of the prototypical Si(111)-(5x2)-Au surface reconstruction, adatoms appear to induce a spontaneous period doubling that is accompanied by an unusual `double' Peierls mechanism. A recent study [4] of 1-D indium chains on Si(111) demonstrated that low energy, anisotropic optical transitions probed by RAS are particularly sensitive probes of 1D behaviour, possibly because the largest 1D exotic effects are expected to be seen near the Fermi level. We present a joint experimental-theoretical study of the structural, electronic and optical properties of nominal and vicinal reconstructed Si(111)-Au surfaces, and interpret the measured reflectance anisotropy spectroscopy (RAS) data of these systems [5]. A phenomenological interpretation of the observed spectra has previously been proposed, but ab initio approaches are necessary for a thorough understanding of the structure and optical response. The role of adatoms, spin-orbit coupling, and higher order effects in the optical response will be addressed[6]. [1] F. Himpsel et al, J. Phys.: Cond. Mat 13, 11097 (2001). [2] N. McAlinden and J. F. McGilp, Euro. Phys. Letters 92, 67008 (2010). [3] S. Erwin et al, Phys. Rev. B 80, 155409 (2009). [4] S. Chandola et al, Phys. Rev. Lett. 102, 226805 (2009). [5] N. McAlinden and J. F. McGilp, J. Phys. Condens. Matter 21, 474208 (2009). [6] C. Hogan, N. McAlinden, and J. F. McGilp, Phys. Status Solidi, accepted (2012)I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
