Nanowires of four epitaxial hexagonal silicides grown on Si(001)

Chen, Yong; Ohlberg, Douglas A. A.; Williams, R. Stanley

doi:10.1063/1.1428807

Cited by 201 publications

(157 citation statements)

References 22 publications

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“…On Si(001), nanowires have been reported for rare earth adatoms, e.g. Gd [27,28], which are believed to form silicide structures that are in fact rather large concerning their diameter. Self-organized formation of silicide nanowires on Si(001) can also be induced, as shown by Preinesberger et al [29].…”

Section: Systems On the Ge(001) Surfacementioning

confidence: 99%

Self-organized atomic nanowires of noble metals on Ge(001): atomic structure and electronic properties

et al. 2009

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Self-organized atomic nanowires of noble metals on Ge(001): atomic structure and electronic properties Abstract. Atomic structures of quasi-one-dimensional (1D) character can be grown on semiconductor substrates by metal adsorption. Significant progress concerning study of their 1D character has been achieved recently by condensing noble metal atoms on the Ge(001) surface. In particular, Pt and Au yield high quality reconstructions with low defect densities. We report on the self-organized growth and the long-range order achieved, and present data from scanning tunneling microscopy (STM) on the structural components. For Pt/Ge(001), we find hot substrate growth is the preferred method for self-organization. Despite various dimerized bonds, these atomic wires exhibit metallic conduction at room temperature, as documented by low-bias STM. For the recently discovered Au/Ge(001) nanowires, we have developed a deposition technique that allows complete substrate coverage. The Au nanowires are extremely well separated spatially, exhibit a continuous 1D charge density, and are of solid metallic conductance. In this review, we present structural details for both types of nanowires, and discuss similarities and differences. A perspective is given for their potential to host a 1D electron system. The ability to condense different noble metal nanowires demonstrates how atomic control of the structure affects the electronic properties.

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Section: Systems On the Ge(001) Surfacementioning

confidence: 99%

Self-organized atomic nanowires of noble metals on Ge(001): atomic structure and electronic properties

et al. 2009

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“…In this respect, RE metal silicides with a hexagonal AlB 2 bulk structure are of particular interest, because they offer tunable Schottky contact resistances [13] and they can grow as long but extremely thin nanowires on (100)-oriented or vicinal (111)-oriented Si substrates [14][15][16][17]. These concepts of strainor step-mediated growth are highly tempting since lithographic problems and limitations are entirely circumvented and, moreover, the metallic wires serve as important model systems to understand the effects of electronic correlation and instabilities characteristic for one-dimensional (1D) physics [4,18].…”

Section: Introductionmentioning

confidence: 99%

Atomic size effects studied by transport in single silicide nanowires

et al. 2016

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Ultrathin metallic silicide nanowires with extremely high aspect ratios can be easily grown, e.g., by deposition of rare earth elements on semiconducting surfaces. These wires play a pivotal role in fundamental research and open intriguing perspectives for CMOS applications. However, the electronic properties of these one-dimensional systems are extremely sensitive to atomic-sized defects, which easily alter the transport characteristics. In this study, we characterized comprehensively TbSi 2 wires grown on Si(100) and correlated details of the atomic structure with their electrical resistivities. Scanning tunneling microscopy (STM) as well as all transport experiments were performed in situ using a four-tip STM system. The measurements are complemented by local spectroscopy and density functional theory revealing that the silicide wires are electronically decoupled from the Si template. On the basis of a quasiclassical transport model, the size effect found for the resistivity is quantitatively explained in terms of bulk and surface transport channels considering details of atomic-scale roughness. Regarding future applications the full wealth of these robust nanostructures will emerge only if wires with truly atomically sharp interfaces can be reliably grown.

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“…The image and cross-sectional line profile can be rationalized by considering the epitaxial relationship between the hexagonal AlB 2 -type structure ( Fig. 2A) of the bulk silicide and the Si(001) substrate, as observed for the rareearth silicide wires (9)(10)(11)(12)(13). In this scenario, the AlB 2 -type structure grows in the (1100) plane orientation with its [1120] direction aligned parallel to one of the < 110 > axes of the Si(001) substrate (Fig.…”

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confidence: 99%

Charge-order fluctuations in one-dimensional silicides

et al. 2008

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Metallic nanowires are of great interest as interconnects in future nanoelectronic circuits. They also represent important systems for understanding the complexity of electronic interactions and conductivity in one-dimension. We have fabricated exceptionally long and uniform YSi 2 nanowires via self-assembly of yttrium atoms on Si(001). The thinnest wires represent one of the closest realizations of the isolated Peierls chain, exhibiting van-Hove type singularities in the onedimensional density of states and charge order fluctuations below 150 K. The structure of the wire was determined though a detailed comparison of scanning tunneling microscopy data and firstprinciples calculations. Sporadic broadenings of the wires' cross section imply the existence of a novel metal-semiconductor junction whose electronic properties are governed by the finite-sizeand temperature-scaling of the charge ordering correlation.One-dimensional (1D) conductors have always captured the imagination of physicists. While a strictly 1D material remains a theoretical construct, a vast number of materials can be viewed as quasi 1D, making them interesting test cases for theoretical predictions and nanoscale applications. Classic examples include charge transfer complexes such as TTF-TCNQ and the Bechgaard salts, which have been studied extensively because of their unusual electrical properties and potential applications as organic conductors (1). These compounds can be viewed as macroscopic ensembles of weakly-coupled quantum chains. They are also textbook illustrations of the venerable Peierls theorem, which states that a 1D metallic chain should be unstable with respect to a symmetry-lowering modulation of the atomic coordinates and valence-charge density (2). The mechanism driving this instability entails the strong coupling between the vibrational modes of the lattice and electrons near the Fermi level. The ground state of a Peierls chain is insulating but the band gap decreases with increasing temperature and metallicity is ultimately restored via a second order phase transition.This simple picture contains some interesting caveats. First of all, the Peierls theory ignores thermodynamic fluctuations. In the 1D limit, thermal fluctuations always destroy long-range order so in principle there is no phase transition (3). Paradoxically, 2D or 3D interchain coupling appears essential for observing the Peierls phase transition in real systems (3). Secondly, the Peierls theory completely ignores electron-electron correlations. Depending on the various interaction parameters, the Peierls transition may be preempted by a competing 'many-body' ground state such as a spin density wave state or Luttinger liquid (1-3). To date, the closest experimental realization of a 1D model system is, arguably, the single-wall carbon nanotube (4-7). Yet, there is no experimental evidence of a Peierls distortion in nanotubes, possibly because the tube diameters are not small enough for observing the transition (5-7). Some experiments even suggest the ex...

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Nanowires of four epitaxial hexagonal silicides grown on Si(001)

Cited by 201 publications

References 22 publications

Self-organized atomic nanowires of noble metals on Ge(001): atomic structure and electronic properties

Self-organized atomic nanowires of noble metals on Ge(001): atomic structure and electronic properties

Atomic size effects studied by transport in single silicide nanowires

Charge-order fluctuations in one-dimensional silicides

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