Electronic distributions in quasicrystalline Al-Pd-Mn alloys

Belin, E.; Dankházi, Zoltán; Sadoc, A.; Dubois, Jean‐Marie

doi:10.1088/0953-8984/6/42/009

Cited by 34 publications

(17 citation statements)

References 24 publications

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“…The intensity between the Pd-derived peak and the Fermi edge has been assigned to states with Mn 3d character 10 , in agreement with x-ray emission spectra from i-Al-Pd-Mn 19 and calculations of the partial density of states (DOS) 20 . A breakdown of the valence level density of states into many very fine spikes, which is predicted from calculations (see, for example, the chapter by Hafner in ref.…”

Section: Results Andsupporting

confidence: 74%

Core and valence level photoemission and photoabsorption study of icosahedral Al–Pd–Mn quasicrystals

Horn¹,

Theis²,

Paggel³

et al. 2005

J. Phys.: Condens. Matter

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The electronic structure of quasicrystalline Al-Pd-Mn is investigated by means of valence and core level photoelectron spectroscopy. Variations of the photoionization cross section in the constituents' valence electronic levels as a function of photon energy are used to identify contributions from the different atomic species, in particular near the Pd 4d Cooper minimum.Resonant photoemission at the Mn 2p absorption edge shows the contribution of the Mn 3d states to the density of states in a region near the Fermi level. The asymmetry of Pd 3d and Mn 2p core level photoemission lines, and its difference for emission from metallic and quasicrystalline phases is utilized to infer the contributions of the different constituents to the density of states at the Fermi level.

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Section: Results Andsupporting

confidence: 74%

Core and valence level photoemission and photoabsorption study of icosahedral Al–Pd–Mn quasicrystals

Horn¹,

Theis²,

Paggel³

et al. 2005

J. Phys.: Condens. Matter

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“…The shoulder at 5 eV is ascribed to the 4d spin splitting [18]. The states below the Fermi level are believed to originate from the Mn 3d states [4,19]. Note that we could not detect the dispersing peak observed in reference [6] at a binding energy of about 2 eV.…”

Section: Edc Of the Qc Crystalline And Disordered Surfacesmentioning

confidence: 63%

“…However there is no accurate determination of the depth of this pseudo-gap. The electronic depletion observed at E F in soft X-ray spectroscopy studies [4] suffers from a limited energy resolution of ∼ 0.1-0.6 eV. In specific heat the linear temperaturea Now at SAP-AG.…”

Section: Introductionmentioning

confidence: 99%

High resolution photoemission spectroscopy study near the Fermi edge for different surfaces prepared on the icosahedral AlPdMn phase

Schaub¹,

Delahaye²,

Berger³

et al. 2001

Eur. Phys. J. B

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High resolution photoemission measurements performed at low temperatures on a single-grained sample of the AlPdMn icosahedral phase show that the density of states N(E) strongly depends on the nature of the surface. For an ordered quasicrystalline surface, prepared by Ar etching and ultra high vacuum annealing, a dip feature is observed in N(E) near the Fermi level, which energy dependence can be analyzed with a simple square-root power law. By contrast, N(E) varies only little with energy both for a disordered surface and a crystalline surface of the same sample. A sharp Fermi edge is then clearly observed. This shows that the metallic character of the surface of a quasicrystal is strongly reduced when the surface presents a quasicrystalline ordering.

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“…19 The existence of the pseudogap near the Fermi level of i-Al-Pd-Mn has been confirmed by many experimental studies. [39][40][41] The presence of a deep pseudogap just above the Fermi level located on the steeply descending part of the DOS also has a substantial effect on the magnetic properties of the quasicrystal.…”

Section: Electronic Structure Of I-al-pd-mn: Bulk and Surfacementioning

confidence: 99%

Magnetism at surfaces and defects in icosahedral Al-Pd-Mn quasicrystals

Krajčı́

Häfner

2009

Phys. Rev. B

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In our recent work ͓Krajčí and Hafner, Phys. Rev. B 78, 224207 ͑2008͔͒ we have demonstrated that the ground state of bulk i-Al-Pd-Mn quasicrystals is nonmagnetic. Mn atoms located at specific sites can acquire a large magnetic moment if they have at least two Pd neighbors in the first coordination shell. Such configurations can be created by substitutional Al/Pd defects which can be formed at low energetic cost because at these sites the overlap between the pseudo-Mackay and Bergman clusters building the quasicrystalline structure leads to conflicting assignments of the chemical decoration. Besides the large magnetic moments formed on these special Mn sites, we have found a broad diffuse background of smaller magnetic moments on many different Mn atoms induced by the large Mn moments. In the present work we extend these investigations to magnetism at the five-fold surface of the quasicrystal and at isolated point defects with particular attention to the formation of induced moments. For the stable five-fold surface we find that Mn atoms located in the surface layer carry indeed large magnetic moments of up to 3 B and that smaller magnetic moments ͑aligned both parallel and antiparallel to the surface moments͒ are induced at distances of up to 10 Å below the surface. We have considered three types of isolated point defects ͑and substitutional defects͒ around a Mn atom and investigated the formation of magnetic moments on the Mn atom and of induced moments on the surrounding sites. For both the magnetization induced below a magnetic surface and the magnetization induced around an Al/Pd substitutional defect, the induced moments show an irregular dependence on the distance from the inducing "source" moment, but a marked dependence on the location of the Mn atom in the occupation domain in six-dimensional hyperspace. Mn atoms with a large coordinate in perpendicular space show large induced moments. Based on the analysis of the local paramagnetic density of states we demonstrate that the formation of a large induced moment is caused by a large polarizability of these Mn atoms, which is related in turn to a rather loosely packed local environment. Per Mn atom, the sum of the source moment ͑created by a special substitutional defect in the bulk quasicrystal or by the reduced coordination of a Mn atom at the surface͒ and of the induced moments reaches values of 6 to 8 B , i.e., much higher than the limit set by Hund's rule for the spin moment of a free Mn atom.

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Electronic distributions in quasicrystalline Al-Pd-Mn alloys

Cited by 34 publications

References 24 publications

Core and valence level photoemission and photoabsorption study of icosahedral Al–Pd–Mn quasicrystals

Core and valence level photoemission and photoabsorption study of icosahedral Al–Pd–Mn quasicrystals

High resolution photoemission spectroscopy study near the Fermi edge for different surfaces prepared on the icosahedral AlPdMn phase

Magnetism at surfaces and defects in icosahedral Al-Pd-Mn quasicrystals

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