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We present a study of the surface structure of the Ag-In-RE (RE: rare-earth elements Gd, Tb, and Yb) complex intermetallics using scanning tunneling microscopy and low-energy electron diffraction. The surface of the Ag-In-Yb approximant prepared by sputter-annealing methods under ultrahigh-vacuum conditions produces a flat (100) surface with no facets. However, the Ag-In-Gd and Ag-In-Tb 1/1 approximants, which have a surface miscut of about 12∘ relative to the (100) plane, develop surface facets along various crystallographic directions. The structure of each facet can be explained as a truncation of the rhombic triacontahedral clusters, i.e., the main building blocks of these systems. Despite their differences in atomic structure, symmetry, and density, the facets show common features. The facet planes are In rich. The analysis of the nearest-neighbor atom distances suggests that In atoms form bonds with the RE atoms, which we suggest is a key factor that stabilizes even low-density facet planes.

We present a study of the surface structure of the Ag-In-RE (RE: rare-earth elements Gd, Tb, and Yb) complex intermetallics using scanning tunneling microscopy and low-energy electron diffraction. The surface of the Ag-In-Yb approximant prepared by sputter-annealing methods under ultrahigh-vacuum conditions produces a flat (100) surface with no facets. However, the Ag-In-Gd and Ag-In-Tb 1/1 approximants, which have a surface miscut of about 12∘ relative to the (100) plane, develop surface facets along various crystallographic directions. The structure of each facet can be explained as a truncation of the rhombic triacontahedral clusters, i.e., the main building blocks of these systems. Despite their differences in atomic structure, symmetry, and density, the facets show common features. The facet planes are In rich. The analysis of the nearest-neighbor atom distances suggests that In atoms form bonds with the RE atoms, which we suggest is a key factor that stabilizes even low-density facet planes.

We present a study of the surface structure of the Ag-In-RE (RE: rare-earth elements Gd, Tb, and Yb) complex intermetallics using scanning tunneling microscopy and low-energy electron diffraction. The surface of the Ag-In-Yb approximant prepared by sputter-annealing methods under ultrahigh-vacuum conditions produces a flat (100) surface with no facets. However, the Ag-In-Gd and Ag-In-Tb 1/1 approximants, which have a surface miscut of about 12∘ relative to the (100) plane, develop surface facets along various crystallographic directions. The structure of each facet can be explained as a truncation of the rhombic triacontahedral clusters, i.e., the main building blocks of these systems. Despite their differences in atomic structure, symmetry, and density, the facets show common features. The facet planes are In rich. The analysis of the nearest-neighbor atom distances suggests that In atoms form bonds with the RE atoms, which we suggest is a key factor that stabilizes even low-density facet planes.

We present a study of the surface structure of the Ag-In-RE (RE: rare-earth elements Gd, Tb, and Yb) complex intermetallics using scanning tunneling microscopy and low-energy electron diffraction. The surface of the Ag-In-Yb approximant prepared by sputter-annealing methods under ultrahigh-vacuum conditions produces a flat (100) surface with no facets. However, the Ag-In-Gd and Ag-In-Tb 1/1 approximants, which have a surface miscut of about 12∘ relative to the (100) plane, develop surface facets along various crystallographic directions. The structure of each facet can be explained as a truncation of the rhombic triacontahedral clusters, i.e., the main building blocks of these systems. Despite their differences in atomic structure, symmetry, and density, the facets show common features. The facet planes are In rich. The analysis of the nearest-neighbor atom distances suggests that In atoms form bonds with the RE atoms, which we suggest is a key factor that stabilizes even low-density facet planes.

We present a study of the surface structure of the Ag-In-RE (RE: rare-earth elements Gd, Tb, and Yb) complex intermetallics using scanning tunneling microscopy and low-energy electron diffraction. The surface of the Ag-In-Yb approximant prepared by sputter-annealing methods under ultrahigh-vacuum conditions produces a flat (100) surface with no facets. However, the Ag-In-Gd and Ag-In-Tb 1/1 approximants, which have a surface miscut of about 12∘ relative to the (100) plane, develop surface facets along various crystallographic directions. The structure of each facet can be explained as a truncation of the rhombic triacontahedral clusters, i.e., the main building blocks of these systems. Despite their differences in atomic structure, symmetry, and density, the facets show common features. The facet planes are In rich. The analysis of the nearest-neighbor atom distances suggests that In atoms form bonds with the RE atoms, which we suggest is a key factor that stabilizes even low-density facet planes.

We present a study of the surface structure of the Ag-In-RE (RE: rare-earth elements Gd, Tb, and Yb) complex intermetallics using scanning tunneling microscopy and low-energy electron diffraction. The surface of the Ag-In-Yb approximant prepared by sputter-annealing methods under ultrahigh-vacuum conditions produces a flat (100) surface with no facets. However, the Ag-In-Gd and Ag-In-Tb 1/1 approximants, which have a surface miscut of about 12∘ relative to the (100) plane, develop surface facets along various crystallographic directions. The structure of each facet can be explained as a truncation of the rhombic triacontahedral clusters, i.e., the main building blocks of these systems. Despite their differences in atomic structure, symmetry, and density, the facets show common features. The facet planes are In rich. The analysis of the nearest-neighbor atom distances suggests that In atoms form bonds with the RE atoms, which we suggest is a key factor that stabilizes even low-density facet planes.

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.

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.

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.

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.

Among the three coexisting types of terraces found on the twofold surface of the d-Al-Cu-Co quasicrystal, nanodomains are essentially observed on the transition-metal rich ones, with a coherent interface boundary. Both clean surface and Ag growth analyses, demonstrate that nanodomain surfaces are structurally identical to one of the two other terraces, which contains 85 at. % Al. We provide evidence that the nanodomains are a manifestation of phason defects that extend downward toward the bulk, and state that nanodomains develop because the energetic cost of creating the phason is outweighed by the change in surface energy. Consequently, the formation of nanodomains involves more than just the surface layer, but is driven by surface energetics., United States. Dept. of Energy (DE-AC02-07CH11358), European Network of Excellence on Complex Metallic Alloys (CMA) (NMP3-CT-2005-500145), France. Agence nationale de la recherche (ANR- 07-Blan-0270)

Among the three coexisting types of terraces found on the twofold surface of the d-Al-Cu-Co quasicrystal, nanodomains are essentially observed on the transition-metal rich ones, with a coherent interface boundary. Both clean surface and Ag growth analyses, demonstrate that nanodomain surfaces are structurally identical to one of the two other terraces, which contains 85 at. % Al. We provide evidence that the nanodomains are a manifestation of phason defects that extend downward toward the bulk, and state that nanodomains develop because the energetic cost of creating the phason is outweighed by the change in surface energy. Consequently, the formation of nanodomains involves more than just the surface layer, but is driven by surface energetics., United States. Dept. of Energy (DE-AC02-07CH11358), European Network of Excellence on Complex Metallic Alloys (CMA) (NMP3-CT-2005-500145), France. Agence nationale de la recherche (ANR- 07-Blan-0270)

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version)

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version)

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version)

We present scanning tunnelling microscopy (STM) studies of the fivefold surface of icosahedral (i) Ag-In-Yb quasicrystals grown under different conditions. The sample grown at a slower rate is found to exhibit impurity phases on the surface, whereas a faster growth rate yields a sample with a structurally perfect surface.

We present scanning tunnelling microscopy (STM) studies of the fivefold surface of icosahedral (i) Ag-In-Yb quasicrystals grown under different conditions. The sample grown at a slower rate is found to exhibit impurity phases on the surface, whereas a faster growth rate yields a sample with a structurally perfect surface.

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version)

We present scanning tunnelling microscopy (STM) studies of the fivefold surface of icosahedral (i) Ag-In-Yb quasicrystals grown under different conditions. The sample grown at a slower rate is found to exhibit impurity phases on the surface, whereas a faster growth rate yields a sample with a structurally perfect surface.

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version)

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version)

We present scanning tunnelling microscopy (STM) studies of the fivefold surface of icosahedral (i) Ag-In-Yb quasicrystals grown under different conditions. The sample grown at a slower rate is found to exhibit impurity phases on the surface, whereas a faster growth rate yields a sample with a structurally perfect surface.

Lead has been deposited on the 10-fold surface of decagonal Al72Ni11Co17 at room temperature to form an epitaxial quasicrystalline single-element monolayer. The overlayer grows through nucleation of nanometer-sized irregular-shaped islands and the coverage saturates at 1 MLE. The overlayer is well-ordered quasiperiodically as evidenced by LEED and Fourier transforms of STM images. LEED measurements also indicate that annealing the film to 600 K improves the structural quality, but STM shows that this causes the film to develop pores. Adsorption of C60 molecules on this surface showed that the pores are Pb-containing. Electronic structure measurements using X-ray photoemission spectroscopy indicate that the chemical interaction of the Pb atoms with the substrate is weak, and that Pb does not desorb from the surface upon annealing.

Lead has been deposited on the 10-fold surface of decagonal Al72Ni11Co17 at room temperature to form an epitaxial quasicrystalline single-element monolayer. The overlayer grows through nucleation of nanometer-sized irregular-shaped islands and the coverage saturates at 1 MLE. The overlayer is well-ordered quasiperiodically as evidenced by LEED and Fourier transforms of STM images. LEED measurements also indicate that annealing the film to 600 K improves the structural quality, but STM shows that this causes the film to develop pores. Adsorption of C60 molecules on this surface showed that the pores are Pb-containing. Electronic structure measurements using X-ray photoemission spectroscopy indicate that the chemical interaction of the Pb atoms with the substrate is weak, and that Pb does not desorb from the surface upon annealing.

The adsorption behaviour of Fe on the tenfold surface of the decagonal quasicrystal Al72.6Ni10.5Co16.9 has been studied using scanning tunnelling microscopy, low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and x-ray magnetic circular dichroism (XMCD). The results show the growth of a disordered film up to a coverage of 9MLE (monolayer equivalent) after which polycrystalline island growth is observed. These islands are interconnected, and the LEED pattern indicates that they preferentially align along five directions. The AES results indicate that the film is composed of Fe intermixed with the substrate elements. The XMCD results point to an induced magnetic moment for Co and Ni in the intermixed layer/interface region.

We present a review of experimental studies of adsorption systems where pseudomorphic growth on quasicrystal surfaces has been observed. From these studies, we correlate information on the known or suggested adsorption and nucleation sites. For fivefold surfaces of icosahedral quasicrystals, two favoured locations emerge: the centres of equatorially truncated pseudo-Mackay clusters, and the centres of pentagonal hollows. The information on adsorption sites on decagonal quasicrystals is less definitive. Nevertheless the correlation of known information leads to a simple picture of pseudomorphic growth, at least for the first monolayer. We also remark on the possibilities for studies using quantitative surface structural techniques.

We present an overview of experimental studies of the structure of adsorbed atomic and molecular species on quasicrystal surfaces with a particular focus on those systems where quasiperiodic ordering of the adsorbate structure occurs. Atomic adsorption is illustrated with examples from studies of Fe and Gd adsorption on the five-fold surface of i-Al-Pd-Mn. Overlayer structure is correlated with several physical parameters to identify trends. It is concluded that the chemical properties of the adsorbate (metallic radius, electronegativity, melting temperature) are important indicators of quasiperiodic structuring of the adsorbate system. These correlations allow predictions of those elements likely to yield pseudomorphic overlayers. Structural effects upon molecular adsorption on clean quasicrystal surfaces have been less successful. A new approach to ordered molecular adsorption is described and illustrated for C60 adsorption on a Pb monolayer film on the ten-fold surface of d-Al-Ni-Co.

We present a review of experimental studies of adsorption systems where pseudomorphic growth on quasicrystal surfaces has been observed. From these studies, we correlate information on the known or suggested adsorption and nucleation sites. For fivefold surfaces of icosahedral quasicrystals, two favoured locations emerge: the centres of equatorially truncated pseudo-Mackay clusters, and the centres of pentagonal hollows. The information on adsorption sites on decagonal quasicrystals is less definitive. Nevertheless the correlation of known information leads to a simple picture of pseudomorphic growth, at least for the first monolayer. We also remark on the possibilities for studies using quantitative surface structural techniques.

We present an overview of experimental studies of the structure of adsorbed atomic and molecular species on quasicrystal surfaces with a particular focus on those systems where quasiperiodic ordering of the adsorbate structure occurs. Atomic adsorption is illustrated with examples from studies of Fe and Gd adsorption on the five-fold surface of i-Al-Pd-Mn. Overlayer structure is correlated with several physical parameters to identify trends. It is concluded that the chemical properties of the adsorbate (metallic radius, electronegativity, melting temperature) are important indicators of quasiperiodic structuring of the adsorbate system. These correlations allow predictions of those elements likely to yield pseudomorphic overlayers. Structural effects upon molecular adsorption on clean quasicrystal surfaces have been less successful. A new approach to ordered molecular adsorption is described and illustrated for C60 adsorption on a Pb monolayer film on the ten-fold surface of d-Al-Ni-Co.

The adsorption behaviour of Fe on the tenfold surface of the decagonal quasicrystal Al72.6Ni10.5Co16.9 has been studied using scanning tunnelling microscopy, low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and x-ray magnetic circular dichroism (XMCD). The results show the growth of a disordered film up to a coverage of 9MLE (monolayer equivalent) after which polycrystalline island growth is observed. These islands are interconnected, and the LEED pattern indicates that they preferentially align along five directions. The AES results indicate that the film is composed of Fe intermixed with the substrate elements. The XMCD results point to an induced magnetic moment for Co and Ni in the intermixed layer/interface region.

The adsorption behaviour of Fe on the tenfold surface of the decagonal quasicrystal Al72.6Ni10.5Co16.9 has been studied using scanning tunnelling microscopy, low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and x-ray magnetic circular dichroism (XMCD). The results show the growth of a disordered film up to a coverage of 9MLE (monolayer equivalent) after which polycrystalline island growth is observed. These islands are interconnected, and the LEED pattern indicates that they preferentially align along five directions. The AES results indicate that the film is composed of Fe intermixed with the substrate elements. The XMCD results point to an induced magnetic moment for Co and Ni in the intermixed layer/interface region.

We present an overview of experimental studies of the structure of adsorbed atomic and molecular species on quasicrystal surfaces with a particular focus on those systems where quasiperiodic ordering of the adsorbate structure occurs. Atomic adsorption is illustrated with examples from studies of Fe and Gd adsorption on the five-fold surface of i-Al-Pd-Mn. Overlayer structure is correlated with several physical parameters to identify trends. It is concluded that the chemical properties of the adsorbate (metallic radius, electronegativity, melting temperature) are important indicators of quasiperiodic structuring of the adsorbate system. These correlations allow predictions of those elements likely to yield pseudomorphic overlayers. Structural effects upon molecular adsorption on clean quasicrystal surfaces have been less successful. A new approach to ordered molecular adsorption is described and illustrated for C60 adsorption on a Pb monolayer film on the ten-fold surface of d-Al-Ni-Co.

We present a review of experimental studies of adsorption systems where pseudomorphic growth on quasicrystal surfaces has been observed. From these studies, we correlate information on the known or suggested adsorption and nucleation sites. For fivefold surfaces of icosahedral quasicrystals, two favoured locations emerge: the centres of equatorially truncated pseudo-Mackay clusters, and the centres of pentagonal hollows. The information on adsorption sites on decagonal quasicrystals is less definitive. Nevertheless the correlation of known information leads to a simple picture of pseudomorphic growth, at least for the first monolayer. We also remark on the possibilities for studies using quantitative surface structural techniques.

Lead has been deposited on the 10-fold surface of decagonal Al72Ni11Co17 at room temperature to form an epitaxial quasicrystalline single-element monolayer. The overlayer grows through nucleation of nanometer-sized irregular-shaped islands and the coverage saturates at 1 MLE. The overlayer is well-ordered quasiperiodically as evidenced by LEED and Fourier transforms of STM images. LEED measurements also indicate that annealing the film to 600 K improves the structural quality, but STM shows that this causes the film to develop pores. Adsorption of C60 molecules on this surface showed that the pores are Pb-containing. Electronic structure measurements using X-ray photoemission spectroscopy indicate that the chemical interaction of the Pb atoms with the substrate is weak, and that Pb does not desorb from the surface upon annealing.

The adsorption behaviour of Fe on the tenfold surface of the decagonal quasicrystal Al72.6Ni10.5Co16.9 has been studied using scanning tunnelling microscopy, low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and x-ray magnetic circular dichroism (XMCD). The results show the growth of a disordered film up to a coverage of 9MLE (monolayer equivalent) after which polycrystalline island growth is observed. These islands are interconnected, and the LEED pattern indicates that they preferentially align along five directions. The AES results indicate that the film is composed of Fe intermixed with the substrate elements. The XMCD results point to an induced magnetic moment for Co and Ni in the intermixed layer/interface region.

We present a review of experimental studies of adsorption systems where pseudomorphic growth on quasicrystal surfaces has been observed. From these studies, we correlate information on the known or suggested adsorption and nucleation sites. For fivefold surfaces of icosahedral quasicrystals, two favoured locations emerge: the centres of equatorially truncated pseudo-Mackay clusters, and the centres of pentagonal hollows. The information on adsorption sites on decagonal quasicrystals is less definitive. Nevertheless the correlation of known information leads to a simple picture of pseudomorphic growth, at least for the first monolayer. We also remark on the possibilities for studies using quantitative surface structural techniques.

Lead has been deposited on the 10-fold surface of decagonal Al72Ni11Co17 at room temperature to form an epitaxial quasicrystalline single-element monolayer. The overlayer grows through nucleation of nanometer-sized irregular-shaped islands and the coverage saturates at 1 MLE. The overlayer is well-ordered quasiperiodically as evidenced by LEED and Fourier transforms of STM images. LEED measurements also indicate that annealing the film to 600 K improves the structural quality, but STM shows that this causes the film to develop pores. Adsorption of C60 molecules on this surface showed that the pores are Pb-containing. Electronic structure measurements using X-ray photoemission spectroscopy indicate that the chemical interaction of the Pb atoms with the substrate is weak, and that Pb does not desorb from the surface upon annealing.

We present an overview of experimental studies of the structure of adsorbed atomic and molecular species on quasicrystal surfaces with a particular focus on those systems where quasiperiodic ordering of the adsorbate structure occurs. Atomic adsorption is illustrated with examples from studies of Fe and Gd adsorption on the five-fold surface of i-Al-Pd-Mn. Overlayer structure is correlated with several physical parameters to identify trends. It is concluded that the chemical properties of the adsorbate (metallic radius, electronegativity, melting temperature) are important indicators of quasiperiodic structuring of the adsorbate system. These correlations allow predictions of those elements likely to yield pseudomorphic overlayers. Structural effects upon molecular adsorption on clean quasicrystal surfaces have been less successful. A new approach to ordered molecular adsorption is described and illustrated for C60 adsorption on a Pb monolayer film on the ten-fold surface of d-Al-Ni-Co.

The elucidation of the local atomic structure of a pseudomorphic film of Cu deposited on the five-fold surface of i- Al70 Pd21 Mn9 using medium-energy ion scattering spectroscopy is reported. Monte Carlo calculations, using the VEGAS code, have been utilized to simulate the blocking of 100 keV He+ ions scattered from the overlayer. The coordinates of the Cu atoms in the overlayer derived from this procedure are consistent with a structure occurring in five rotational domains. Each domain consists of nanoscale strips of fcc Cu(100) with the 110 azimuth aligned along the five-fold directions of the quasicrystalline substrate. The strips are arranged according to a one-dimensional Fibonacci sequence with long and short widths related by the golden mean τ. Upon annealing the film transforms to an alloyed structure composed of five orientational domains of fcc material with the (110) axis perpendicular to the surface.

The elucidation of the local atomic structure of a pseudomorphic film of Cu deposited on the five-fold surface of i- Al70 Pd21 Mn9 using medium-energy ion scattering spectroscopy is reported. Monte Carlo calculations, using the VEGAS code, have been utilized to simulate the blocking of 100 keV He+ ions scattered from the overlayer. The coordinates of the Cu atoms in the overlayer derived from this procedure are consistent with a structure occurring in five rotational domains. Each domain consists of nanoscale strips of fcc Cu(100) with the 110 azimuth aligned along the five-fold directions of the quasicrystalline substrate. The strips are arranged according to a one-dimensional Fibonacci sequence with long and short widths related by the golden mean τ. Upon annealing the film transforms to an alloyed structure composed of five orientational domains of fcc material with the (110) axis perpendicular to the surface.

The two-fold surface of the icosahedral quasicrystal Al 70.2Pd 21.5Mn 8.3 prepared in UHV has been studied with LEED and STM. Two phases are observed: a quasiperiodic phase, in agreement with previous work, and a periodic phase tentatively identified as orthorhombic. Copper deposition on the two-fold surface leads to a multilayer exhibiting a quasiperiodic LEED pattern.

The two-fold surface of the icosahedral quasicrystal Al 70.2Pd 21.5Mn 8.3 prepared in UHV has been studied with LEED and STM. Two phases are observed: a quasiperiodic phase, in agreement with previous work, and a periodic phase tentatively identified as orthorhombic. Copper deposition on the two-fold surface leads to a multilayer exhibiting a quasiperiodic LEED pattern.

The two-fold surface of the icosahedral quasicrystal Al70.2Pd21.5Mn8.3 prepared in UHV has been studied with LEED and STM. Two phases are observed: a quasiperiodic phase, in agreement with previous work, and a periodic phase tentatively identified as orthorhom- bic. Copper deposition on the two-fold surface leads to a multilayer exhibiting a quasiperiodic LEED pattern.

The two-fold surface of the icosahedral quasicrystal Al70.2Pd21.5Mn8.3 prepared in UHV has been studied with LEED and STM. Two phases are observed: a quasiperiodic phase, in agreement with previous work, and a periodic phase tentatively identified as orthorhom- bic. Copper deposition on the two-fold surface leads to a multilayer exhibiting a quasiperiodic LEED pattern.

The adsorption behaviour of Co on the tenfold surface of d -Al 72 Ni 11 Co 17 and on the fivefold surface of i -Al 70 Pd 21 Mn 9 has been studied using scanning tunnelling microscopy (STM), Auger electron spectroscopy (AES) and low-energy electron diffraction (LEED). The analysis of a distinctive quasiperiodic LEED pattern for coverages from 3-30?ML of Co on d -Al 72 Ni 11 Co 17 suggests that the Co forms in a pseudomorphic row structure composed of domains of Fibonacci spaced rows having a periodic lattice parameter along the rows of 2.50.1. The same structure, though less well-ordered and with a larger lattice parameter, is formed on the fivefold surface of i -Al 70Pd21Mn9.

The two-fold surface of the icosahedral quasicrystal Al70.2Pd21.5Mn8.3 prepared in UHV has been studied with LEED and STM. Two phases are observed: a quasiperiodic phase, in agreement with previous work, and a periodic phase tentatively identified as orthorhom- bic. Copper deposition on the two-fold surface leads to a multilayer exhibiting a quasiperiodic LEED pattern.

The two-fold surface of the icosahedral quasicrystal Al 70.2Pd 21.5Mn 8.3 prepared in UHV has been studied with LEED and STM. Two phases are observed: a quasiperiodic phase, in agreement with previous work, and a periodic phase tentatively identified as orthorhombic. Copper deposition on the two-fold surface leads to a multilayer exhibiting a quasiperiodic LEED pattern.

The adsorption behaviour of Co on the tenfold surface of d -Al 72 Ni 11 Co 17 and on the fivefold surface of i -Al 70 Pd 21 Mn 9 has been studied using scanning tunnelling microscopy (STM), Auger electron spectroscopy (AES) and low-energy electron diffraction (LEED). The analysis of a distinctive quasiperiodic LEED pattern for coverages from 3-30?ML of Co on d -Al 72 Ni 11 Co 17 suggests that the Co forms in a pseudomorphic row structure composed of domains of Fibonacci spaced rows having a periodic lattice parameter along the rows of 2.50.1. The same structure, though less well-ordered and with a larger lattice parameter, is formed on the fivefold surface of i -Al 70Pd21Mn9.

The two-fold surface of the icosahedral quasicrystal Al70.2Pd21.5Mn8.3 prepared in UHV has been studied with LEED and STM. Two phases are observed: a quasiperiodic phase, in agreement with previous work, and a periodic phase tentatively identified as orthorhom- bic. Copper deposition on the two-fold surface leads to a multilayer exhibiting a quasiperiodic LEED pattern.

The two-fold surface of the icosahedral quasicrystal Al 70.2Pd 21.5Mn 8.3 prepared in UHV has been studied with LEED and STM. Two phases are observed: a quasiperiodic phase, in agreement with previous work, and a periodic phase tentatively identified as orthorhombic. Copper deposition on the two-fold surface leads to a multilayer exhibiting a quasiperiodic LEED pattern.