Optical properties of calaverite, AuTe2

Dijkstra, Edsger W.; Kremers, M.; Devillers, M.A.C.

doi:10.1007/bf01307899

Cited by 5 publications

(3 citation statements)

References 14 publications

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“…The absence of significant core-level splitting predicted by our calculations is in agreement with the XPS data of van Triest et a1 [19], who observe no splitting for the Au core levels. For the Te levels they see an interesting phenomenon, which seems to fit in with the experience of other experimentalists [6]. There is a splitting of the Te states of several electronvolts, which is angle-and time-dependent and therefore attributed to a surface reconstruction following the scraping of the sample surface.…”

Section: Mixed Valenciessupporting

confidence: 80%

First-principles electronic structure calculations for incommensurately modulated calaverite

Krutzen

Inglesfield

1990

J. Phys.: Condens. Matter

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Fully relativistic first-principles electronic structure calculations of both the average structure and a supercell approximation of silver-free incommensurately modulated calaverite (AuTe2) are presented. The differences between the results of both calculations are relatively small for the occupation numbers and the density of states, but quite dramatic for the shape of the Fermi surface. From the occupation numbers it is concluded that a previously proposed idea for explaining the modulation, based on mixed valencies for the gold atoms, is probably not applicable. The calculated Fermi surface of the average structure shows that the modulation cannot be understood in terms of Fermi-surface nesting either. The density of states in the supercell approximation compares very favourably with recently obtained X-ray photoelectron spectroscopy data. A rigid-potential calculation shows that the integral of the one-electron valence energies for the supercell is substantially more negative than the corresponding energy for the average structure, while the electrostatic energy difference has the opposite sign but is much smaller. This provides a qualitative indication of the electronic instability of the average structure with respect to the modulation of the supercell. Finally the authors conclude that Te s-like states a (Te p-Au d)-like complex dominate the energetics of the modulation.

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Section: Mixed Valenciessupporting

confidence: 80%

First-principles electronic structure calculations for incommensurately modulated calaverite

Krutzen

Inglesfield

1990

J. Phys.: Condens. Matter

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“…This indicates the presence of two types of Te atom after two days. We remark that a difference between afreshly prepared surface and the surface after two days was also observed in the optical properties [24].…”

Section: Te 4d and Te 3d Spectramentioning

confidence: 56%

Electronic structure and photoelectron spectra of calaverite, AuTe₂

Triest¹,

Folkerts²,

Haas³

1990

J. Phys.: Condens. Matter

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Photoelectron spectra of calaverite, AuTe2, show a Au 5d band extending from -3 to -8 eV below the Fermi energy. Photoemission peaks from Au 4f core levels are sharp, indicating that all Au atoms have the same valency. The binding energies of Au 4f electrons in AuTe2 and metallic Au are approximately the same. According to these observations all Au atoms in AuTe2 are monovalent Au(I). Photoelectron spectra of Te 4d and 3d core levels show single sharp peaks, characteristic of a single valency for Te. These investigations clearly establish the absence of appreciable valency fluctuations or mixed valency Au(I)-Au(III) in AuTe2.

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“…Crack lines, facets looking as if they were broken and step patterns (figure 7) do occur. Characterization using techniques such as phase contrast and differential interference contrast microscopy, XPS, STM and ellipsometry [18], is in progress.…”

Section: Kyropoulos Techniquementioning

confidence: 99%

Morphology and crystal growth of pure calaverite

Balzuweit¹,

Meekes²,

Bennema³

1991

J. Phys. D: Appl. Phys.

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Some preliminary results of artificial growth of the incommensurately modulated mineral calaverite are presented. Using different growth techniques such as Bridgman and Kyropoulos the authors obtained relatively large single crystals of AuTe2 (up to 50 mm in length) with facets. The crystals were characterized by use of SEM imaging and microprobe, Laue backscattering and optical goniometry. Using a four-dimensional description for the morphology, indexing of both main and satellite faces was possible.

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Optical properties of calaverite, AuTe2

Cited by 5 publications

References 14 publications

First-principles electronic structure calculations for incommensurately modulated calaverite

First-principles electronic structure calculations for incommensurately modulated calaverite

Electronic structure and photoelectron spectra of calaverite, AuTe₂

Morphology and crystal growth of pure calaverite

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Optical properties of calaverite, AuTe2

Cited by 5 publications

References 14 publications

First-principles electronic structure calculations for incommensurately modulated calaverite

First-principles electronic structure calculations for incommensurately modulated calaverite

Electronic structure and photoelectron spectra of calaverite, AuTe2

Morphology and crystal growth of pure calaverite

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Product

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About

Electronic structure and photoelectron spectra of calaverite, AuTe₂