Optical Response of fci-ZnMgHo Quasicrystal

Karpus, V.; Babonas, G.-J.; Rėza, A.; Suchodolskis, A.; Tumėnas, Saulius; Hunderi, O.; Aßmus, W.; Brühne, Stefan

doi:10.12693/aphyspola.113.1005

Cited by 4 publications

(5 citation statements)

References 7 publications

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“…The w p ' 10 eV estimate obtained agrees in an order of magnitude with the w p ¼ 12:7 eV value, determined by the plasma frequency formula w p ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 4pe 2 n=m 0 p (where n ¼ 1:17 Â 10 23 cm À3 is the si-ZnMgHo valence electron concentration and m 0 is the free electron mass), and with the w p ' 11 eV estimate for the fci-ZnMgHo phase [5]. The dispersion of the si-ZnMgHo dielectric function and the optical conductivity ( Fig.…”

Section: Dielectric Function and Optical Conductivitysupporting

confidence: 82%

Optical response of si-ZnMgHo quasicrystal

Karpus¹,

Babonas²,

Rėza³

et al. 2009

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract. The results of room-temperature optical study of single-grain simple icosahedral ZnMgHo quasicrystals are presented. The dielectric function eðwÞ of the quasicrystals was measured by spectroscopic ellipsometry technique in the spectral range of 0:1À7 eV. The si-ZnMgHo optical response is a superposition of the free-electron Drude-type contribution and that of the interband transitions. The experimental eðwÞ spectra are well simulated within a framework of the 'band structure hypothesis'. The deduced parameters of the si-ZnMgHo electron energy spectrum are close to their values determined previously in an analysis of the si-ZnMgHo photoemission data.

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Section: Dielectric Function and Optical Conductivitysupporting

confidence: 82%

Optical response of si-ZnMgHo quasicrystal

Karpus¹,

Babonas²,

Rėza³

et al. 2009

Zeitschrift Für Kristallographie - Crystalline Materials

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“…Within the mass of the work made on the physical characterization of these materials, optical properties were found to be rather difficult to be interpreted. For instance, Karpus et al 13 underlined that the measured data were complex and stressed on the importance of the quality of the samples. This is of course well known from all material scientists and physicists : purity and structural quality of samples are of high relevance to identify their canonical physical properties.…”

Section: Introductionmentioning

confidence: 99%

Optical reflectivity as a simple diagnostic method for testing structural quality of icosahedral quasicrystals

Brien¹,

Dauscher

Machizaud³

2006

Journal of Applied Physics

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The optical reflectivity of Al-based and Ti-based quasicrystalline and approximant samples were investigated versus the quality of their structural morphology using optical reflectometry, X-ray diffraction and transmission electron microscopy. The different structural morphologies were obtained using three different preparation processes : sintering, pulsed laser deposition and reactive cathodic magnetron sputtering. The work demonstrates that the canonical behaviour of icosahedral state in specular reflectivity is extremely sensitive to different and very fine aspects of the microstructure : sizes of grains smaller than 50 nm, slight local diffuse disorder and shifts away from the icosahedral crystallographic structure (approximants). The work explains why the optical properties of the same kind of quasicrystals found in literature sometimes reveal a different behaviour from one author to another. The study then confirms the work of some authors and definitely shows that the canonical behaviour of icosahedral state in specular reflectivity over the 30000 -50000 cm -1 domain is characterized by a decreasing function made of steps. It also shows that this behaviour can be interpreted thanks to the cluster hierarchy of the model of Janot.

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“…Indeed, the spectral weight of the interband transitions, ∞ 0 dω Reσ ib (ω), as can be easily proved by a straightforward integration of the K-kernel (14), is given by the formula…”

Section: B Intraband Optical Conductivitymentioning

confidence: 99%

“…In the limit of weak scattering, when g , the K kernel (14) reduces to the form (27) and the real part of the interband conductivity is easily calculated due to a simple integration with the δ(x − z) function. The interband absorption line/band due to a single Bragg plane acquires the form…”

Section: Weak Scattering Limitmentioning

confidence: 99%

“…Our previous preliminary spectroscopic ellipsometry studies [12][13][14] of icosahedral Zn-Mg-R quasicrystals (where R = Y, Ho, Er), as well as reflection spectroscopy studies of Zn-Mg-Y and Zn-Mg-Tb by Chernikov et al, 15 revealed a strong interband optical feature at about 1 eV, but a larger Drude peak as compared to that in Al-based quasicrystals.…”

Section: Introductionmentioning

confidence: 99%

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Optical spectroscopy and electronic structure of the face-centered icosahedral quasicrystals Zn-Mg-R(R=Y, Ho, Er)

et al. 2013

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Results of optical spectroscopy studies of the face-centered icosahedral (fci) single-grain Zn-Mg-Y, Zn-Mg-Ho, and Zn-Mg-Er quasicrystals (QCs) are presented. The dielectric function of the QCs was measured in the 0.01-6 eV spectral range by IR-UV spectroscopic ellipsometry and far infrared reflection spectroscopy techniques. A theoretical scheme of optical conductivity calculations is extended to account for the Fermi level positions within and below a pseudogap. The model of the QC electron energy spectrum, based on a band structure hypothesis, is suggested, which treats the electronic subsystem as a nearly free electron gas affected by intersections of the Fermi surface with several families of Bragg planes. The experimental optical spectra are reproduced in detail by theoretical calculations carried out within the framework of the model. The parameters of the electron energy spectrum deduced from an analysis of optical data are close to those previously determined in an analysis of fci Zn-Mg-R valence band photoemission spectra.

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Optical Response of fci-ZnMgHo Quasicrystal

Cited by 4 publications

References 7 publications

Optical response of si-ZnMgHo quasicrystal

Optical response of si-ZnMgHo quasicrystal

Optical reflectivity as a simple diagnostic method for testing structural quality of icosahedral quasicrystals

Optical spectroscopy and electronic structure of the face-centered icosahedral quasicrystals Zn-Mg-R(R=Y, Ho, Er)

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