Quantum size effects arising from incompatible point-group symmetries: Angle-resolved photoemission study

Moras, Paolo; Weisskopf, Y.; Longchamp, Jean-Nicolas; Erbudak, M.; Zhou, P. H.; Ferrari, L.; Carbone, C.

doi:10.1103/physrevb.74.121405

Cited by 20 publications

(32 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Then minimization of the electronic energy favors preferred thickness of the Bi islands. 9 Quantum size effects were later confirmed by Moras et al 11 who directly observed sp-derived quantum well states by photoemission spectroscopy in Ag thin films deposited on quasicrystalline templates. It was argued that the confining barrier is mainly driven by the incompatible symmetries of the wave functions at the film substrate interface rather than by the pseudogap in the electronic structure of the substrate.…”

Section: Introductionsupporting

confidence: 53%

“…We hypothesized that the origin of the confinement at the film/substrate interface could be due to the reduced density of states at the Fermi characteristic of these alloys. Later, Moras et al 11 directly observed by photoemission spectroscopy the quantum well states in Ag thin films deposited on either the fivefold surface of i-Al-Pd-Mn or the tenfold surface of d-Al-Ni-Co, thus confirming the suggested electronic growth mechanism. However, it was found that these quantum well states did not display any dependence on the density of states of the quasicrystalline substrates, which are significantly different for both substrates.…”

Section: Interpretation Of Magic Heightsmentioning

confidence: 69%

See 1 more Smart Citation

Growth of Bi thin films on quasicrystal surfaces

et al. 2008

View full text Add to dashboard Cite

We present a comprehensive study of Bi thin-film growth on quasicrystal surfaces. The substrates used for the growth are the fivefold surface of icosahedral (i)-Al-Cu-Fe and i-Al-Pd-Mn and the tenfold surface of decagonal (d)-Al-Ni-Co quasicrystals. The growth is investigated at 300 and 525 K substrate temperatures and at different coverage (θ) ranging from submonolayer to ten monolayers. The film is characterized by scanning tunneling microscopy, reflection high-energy electron diffraction, and x-ray photoelectron spectroscopy. At 300 K, the deposited Bi yields a quasicrystalline film for θ≤1. For 1<θ<5, it forms nanocrystallites with (100) surface orientation. The islands have magic heights, which correspond to the stacking of four atomic layers (predominantly). The selection of magic heights is interpreted in terms of quantum size effects arising from the electron confinement within the film thickness. The islands establish rotational epitaxial relationship with the substrate. For higher coverage, the film grows with monatomic height, not with magic heights, and reflects the symmetry of the bulk Bi. When deposition is performed at 525 K, terrace diffusion is more effective, resulting in the aggregation of Bi adatoms developing into a smooth monolayer with quasiperiodic order. At this temperature, multilayers do not adsorb. Disciplines Condensed Matter Physics | Metallurgy CommentsThis article is from Physical Review B 78 (2008) We present a comprehensive study of Bi thin-film growth on quasicrystal surfaces. The substrates used for the growth are the fivefold surface of icosahedral ͑i͒-Al-Cu-Fe and i-Al-Pd-Mn and the tenfold surface of decagonal ͑d͒-Al-Ni-Co quasicrystals. The growth is investigated at 300 and 525 K substrate temperatures and at different coverage ͑ ͒ ranging from submonolayer to ten monolayers. The film is characterized by scanning tunneling microscopy, reflection high-energy electron diffraction, and x-ray photoelectron spectroscopy. At 300 K, the deposited Bi yields a quasicrystalline film for Յ 1. For 1 Ͻ Ͻ 5, it forms nanocrystallites with ͑100͒ surface orientation. The islands have magic heights, which correspond to the stacking of four atomic layers ͑predominantly͒. The selection of magic heights is interpreted in terms of quantum size effects arising from the electron confinement within the film thickness. The islands establish rotational epitaxial relationship with the substrate. For higher coverage, the film grows with monatomic height, not with magic heights, and reflects the symmetry of the bulk Bi. When deposition is performed at 525 K, terrace diffusion is more effective, resulting in the aggregation of Bi adatoms developing into a smooth monolayer with quasiperiodic order. At this temperature, multilayers do not adsorb.

show abstract

Section: Introductionsupporting

confidence: 53%

Section: Interpretation Of Magic Heightsmentioning

confidence: 69%

Growth of Bi thin films on quasicrystal surfaces

et al. 2008

View full text Add to dashboard Cite

show abstract

“…This interpretation was later disputed by a photoemission study on Ag/i-Al-Pd-Mn. It was argued instead that the confinement arises from incompatible symmetries of electronic states in the quasi-crystalline substrate and crystalline film such that no coupling of electron wave functions occurs at the interface [37]. These islands have pseudo-cubic structure with the {100} surface orientation.…”

Section: On I-al-pd-mn As Well As On I-al-cu-fe and D-al-ni-comentioning

confidence: 99%

The memory of surfaces: epitaxial growth on quasi-crystals

McGrath

Sharma

Smerdon

et al. 2012

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

If crystal structures can be viewed as repositories of information, then crystal surfaces offer a pathway by which this information can be used to grow new structures through the process of epitaxy. The information transfer process is one of self-organization, and the kinetic and energetic factors influencing this are complex. They include the relative strengths of the adsorbate-adsorbate and adsorbate-substrate interactions, the flux of incoming species and the temperature of the system. In this brief review, we explore how the interplay of these factors influences the degree to which the epitaxial structures retain the 'memory' of the template, illustrating the discussion with examples from epitaxy on quasi-crystal surfaces.

show abstract

“…If bilayer formation were the only effect responsible, a significant fraction of islands having 6 AL would also be expected to occur, particularly at the higher of the two coverages investigated here. The most obvious additional factor that might be responsible would be quantum size effects, such as those seen for Ag on d-Al-Ni-Co. 16 However, Bi is only a semi-metal in its native rhombohedral state, and for the black-phosphoruslike phase, both theoretical calculations and scanning tunneling spectroscopy measurements of similar Bi clusters on Si͑111͒ indicate a reduction in the local density of states at the Fermi level, leading to reduced metallic nature in the islands. 17 Clearly, the islands must retain some metallic character for quantum well states to occur.…”

Section: Structure Of the Bi Islandsmentioning

confidence: 99%

“…Later work concerning thin films of Ag on d-Al 72 Ni 11 Co 17 and i-Al 71 Pd 20 Mn 9 demonstrated the presence of quantum well states in these systems but also indicated that the quantum confinement was not due to the low density of states at the Fermi level seen in quasicrystalline materials ͑the so-called pseudogap͒, but rather due to the incompatibility of the substrate and overlayer symmetries which preclude electronic coupling. 16 Although the quantum size effects provide a good explanation of the preference for 4 AL high islands seen for Bi on i-Al 71 Pd 20 Mn 9 and related systems, there is another potential explanation which comes from work carried out on the closely related system of Bi films grown on Si͑111͒. 17,18 In this system, as with growth on quasicrystalline surfaces, a monolayer film of Bi is seen to form, on top of which Bi islands of 4 AL height grow, as demonstrated by STM studies.…”

Section: Introductionmentioning

confidence: 99%

Two- and three-dimensional growth of Bi oni-Al-Pd-Mn studied using medium-energy ion scattering

et al. 2010

View full text Add to dashboard Cite

Recent work on the growth of thin metal films on quasicrystalline substrates has indicated the formation of so-called "magic height" islands with multiples of 4 atomic layers ͑AL͒ arising as a result of quantum size effects, which lead to enhanced stability. Here the results of a study are reported of Bi deposition on i-Al-Pd-Mn using medium-energy ion scattering to characterize the island thickness and the structural arrangement of Bi atoms within the islands. In addition, data were taken from annealed surfaces after Bi cluster desorption to leave a single aperiodic monolayer of Bi at the surface. Scattered-ion energy spectra from the Bi islands are consistent with a single Bi monolayer covered with mainly 4 AL islands for both 1.8 and 3.2 monolayer equivalent coverages but with some occupation of 2 and 8 Al islands as well. The angular dependence of the scattered-ion intensity ͑"blocking curve"͒ from Bi has been compared with simulations for various models of both rhombohedral Bi and a distorted "black-phosphorus"-like structure. The data demonstrate bilayer formation within the Bi islands. In the case of the aperiodic Bi monolayer, the blocking curves from substrate scattering are found to be inconsistent with two high-symmetry sites on the quasicrystalline surface that theory indicates are energetically favorable but do not exclude the formation of pentagonal arrangements of Bi atoms as seen in other recent experimental work.

show abstract

Quantum size effects arising from incompatible point-group symmetries: Angle-resolved photoemission study

Cited by 20 publications

References 19 publications

Growth of Bi thin films on quasicrystal surfaces

Growth of Bi thin films on quasicrystal surfaces

The memory of surfaces: epitaxial growth on quasi-crystals

Two- and three-dimensional growth of Bi oni-Al-Pd-Mn studied using medium-energy ion scattering

Contact Info

Product

Resources

About