Electronic structure of atomic chains on vicinal Si(111)-Au

Altmann, K. N.; Crain, Jason; Kirakosian, A.; Lin, Ja‐Chen; Petrovykh, Dmitri Y.; Himpsel, F. J.; Losio, R.

doi:10.1103/physrevb.64.035406

Cited by 135 publications

(127 citation statements)

References 48 publications

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“…As with the Ag, the Fermi surface of α √3×√3 -Au has a single pocket centered at the √3×√3 Γ point. This corresponds to a metallic surface state reported in earlier photoemission and inverse photoemission studies [29,33,34]. The exact shape of the Fermi surface is difficult to determine because of its asymmetry across the Γ point in both the x and y directions, and the general broadness of the band.…”

Section: Si(111) 3u 3-aumentioning

confidence: 99%

Fermi surfaces of surface states on Si(111)-Ag, Au

et al. 2002

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Metallic surface states on semiconducting substrates provide an opportunity to study low-dimensional electrons decoupled from the bulk. Angle resolved photoemission is used to determine the Fermi surface, group velocity, and effective mass for surface states on Si(111)√3×√3-Ag, Si(111)√3×√3-Au, and Si(111)√21×√21-(Ag+Au). For Si(111)√3×√3-Ag the Fermi surface consists of small electron pockets populated by electrons from a few % excess Ag. For Si(111)√21×√21-(Ag+Au) the added Au forms a new, metallic band. The √21×√21 superlattice leads to an intricate surface umklapp pattern and to minigaps of 110 meV, giving an interaction potential of 55 meV for the √21×√21 superlattice.

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Section: Si(111) 3u 3-aumentioning

confidence: 99%

Fermi surfaces of surface states on Si(111)-Ag, Au

et al. 2002

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“…[16][17][18][19] In the case of 1D systems other than Y-123, modifications to the spectral function with the onset of the CDW state have been detected as well. [20][21][22] the emergence of a pseudogap-like state is also expected in theory and can be understood as a result of a fluctuating Peierls order parameter. [23][24][25][26][27] At the same time, despite the abundant evidence for charge modulations in direct space provided by STM, Y-123 chains seem to exhibit neither a pseudogap nor the Tomonaga-Luttinger behavior observed in the related PrBa 2 Cu 4 O 8 .…”

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Pseudogap in the chain states of YBa2Cu3O6.6

et al. 2012

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As established by scanning tunneling microscopy (STM) cleaved surfaces of the high temperature superconductor YBa 2 Cu 2 O 7−δ develop charge density wave (CDW) modulations in the one-dimensional (1D) CuO chains. At the same time, no signatures of the CDW have been reported in the spectral function of the chain band previously studied by photoemission. We use soft X-ray angle resolved photoemission (SX-ARPES) to detect a chain-derived surface band that had not been detected in previous work. The 2k F for the new surface band is found to be 0.55 Å −1 , which matches the wave vector of the CDW observed in direct space by STM. This reveals the relevance of the Fermi surface nesting for the formation of CDWs in the CuO chains in YBa 2 Cu 2 O 7−δ . In agreement with the short range nature of the CDW order the newly detected surface band exhibits a pseudogap, whose energy scale also corresponds to that observed by STM. PACS numbers: 71.45.Lr , 74.72.Kf, 79.60.Jv The CuO chain structure in YBa 2 Cu 2 O 7−δ (Y-123) provides a physical realization of a quasi-one-dimensional electronic system with non-vanishing coupling to the CuO 2 bilayers. 1,2 One of the reasons why 1D electronic systems remain in the focus of solid state research is that even weak interactions transform the quasi-particles of Fermi liquid theory into collective excitations of density wave type. [3][4][5] In particular, the peculiar topological structure of the chain Fermi surface (FS) makes this electronic system prone to formation of charge density wave via the Peierls instability. 6 Indeed, charge density modulations along the Cu-O chains have been extensively studied probing cleaved surfaces of Y-123 in direct space with scanning tunneling microscopy. [7][8][9][10][11][12][13][14][15] It has been shown that Y-123 crystals cleave between the CuO chains and the BaO layer, so that the chains turn out to be the nearest to the surface building block. 7,9,10,15 Both the earliest 9 and the most recent studies 14 present a consistent picture of a CDW, appearing as corrugations of the electronic density with a short correlation range of about 40 Å and a period between 9 and 14 Å, depending on the sample stoichiometry.In the case of 2D systems, the effect of CDW on the electronic states in the reciprocal space has been examined in great detail with modern angle resolved spectroscopy, which provides both momentum and energy resolution when measuring the one particle spectral function. Occurrences of the pseudogap for an incommensurate (or short range ordered) state, which finally develops into a true CDW band gap below T CDW , are well documented. [16][17][18][19] In the case of 1D systems other than Y-123, modifications to the spectral function with the onset of the CDW state have been detected as well. 20-22 the emergence of a pseudogap-like state is also expected in theory and can be understood as a result of a fluctuating Peierls order parameter. [23][24][25][26][27] At the same time, despite the abundant evidence for charge modulations in direct spa...

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“…By utilizing a specific miscut angle and annealing procedure, regular arrays of steps with spacings ranging from 2 to 80 nm can be prepared. 17,18 Gold grown on Si͑111͒ at a thickness of 3 nm still preserves the well-defined bunched step nanopattern. 16 A titanium adhesion layer facilitates the smooth growth of the gold.…”

Section: Introductionmentioning

confidence: 99%

Functionalization of silicon step arrays II: Molecular orientation of alkanes and DNA

Crain

Kirakosian

Lin

et al. 2001

Journal of Applied Physics

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Alkanes and DNA are adsorbed via thiol groups on ultrathin gold films that have been templated on stepped Si(111)7ϫ7 surfaces. The orientation of the adsorbed molecules is determined by polarization-dependent near edge x-ray absorption fine structure spectroscopy from the C 1s and N 1s core levels. An anisotropy in the polar distribution is found which is consistent with models in which the molecules have a preferred tilt angle with respect to normal but a random azimuthal distribution. In order to obtain maximum coverage and an oriented overlayer it is necessary to deposit more than 3 nm of Au ͑12 monolayers͒.

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Electronic structure of atomic chains on vicinal Si(111)-Au

Cited by 135 publications

References 48 publications

Fermi surfaces of surface states on Si(111)-Ag, Au

Fermi surfaces of surface states on Si(111)-Ag, Au

Pseudogap in the chain states of YBa2Cu3O6.6

Functionalization of silicon step arrays II: Molecular orientation of alkanes and DNA

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