Multiplet effects in the electronic structure of intermediate-valence compounds

Polycrystalline samples of YNi 2 B 2 C and magnetic ErNi 2 B 2 C prepared by arc melting technique have been investigated. Resistivity and magnetization measurements yield superconducting transition temperatures for the two samples of ~ 15 K and ~ 11 K respectively. Core level spectroscopic studies on C (1s), B (1s), Ni (2p), Er (4d) and Y (3d) as well as valence band measurements were performed in order to investigate the electronic structure. The results are interpreted to deduce the valence of Y, Er and Ni. Ni is found to exist in 2+ and y in 3+ valence state. The Er spectra indicate that Er may either be in an intermediate valence state or some minor impurity phase.

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Effect of the d-f correlation on the electronic structure of intermediate valence systems

Solid State Communications ◽

10.1016/0038-1098(85)90954-8 ◽

1985 ◽

Vol 56 (7) ◽

pp. 557-561 ◽

Cited By ~ 2

Author(s):

J.R. Iglesias ◽

P.M. Mors

Keyword(s):

Electronic Structure ◽

Intermediate Valence

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Low-energy electronic structure of intermediate-valence "golden" SmS

Physical Review B ◽

10.1103/physrevb.30.5877 ◽

1984 ◽

Vol 30 (10) ◽

pp. 5877-5883 ◽

Cited By ~ 41

Author(s):

G. Travaglini ◽

P. Wachter

Keyword(s):

Electronic Structure ◽

Low Energy ◽

Intermediate Valence

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The Influence of Ce on the Electrical Resistivity and Electronic Structure in the Gd1-xCexIn3 Compounds

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.194.35 ◽

2012 ◽

Vol 194 ◽

pp. 35-39 ◽

Cited By ~ 2

Author(s):

Anna Bajorek ◽

Grażyna Chełkowska ◽

Artur Chrobak ◽

Marzena Kwiecień Grudziecka

Keyword(s):

Crystal Structure ◽

Electrical Resistivity ◽

Electronic Structure ◽

Cell Parameter ◽

Linear Increase ◽

Intermediate Valence ◽

Metallic Behavior ◽

Level Lines ◽

Ce Substitution ◽

Ce Content

All studied Gd1-xCexIn3 compounds crystallize in the cubic AuCu3 - type of crystal structure. The influence of Gd/Ce substitution is reflected in the linear increase of the unit cell parameter. The temperature dependence of the electrical resistivity ρ(T) strongly depends on the Ce content. For compounds with x≤0.2 a typical metallic behavior has been observed. In contrary, for Ce-rich compounds (x≥0.5) a characteristic Kondo-type behaviour has been noticed. The analysis of cerium XPS core level lines reveals the occurrence of possible Ce intermediate valence.

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Racah Materials: Role of Atomic Multiplets and Intermediate Valence in f-Electron Systems

MRS Advances ◽

10.1557/adv.2016.358 ◽

2016 ◽

Vol 1 (44) ◽

pp. 2967-2974 ◽

Cited By ~ 1

Author(s):

A. I. Lichtenstein ◽

J. Kolorenc ◽

A. B. Shick ◽

M. I. Katsnelson

Keyword(s):

Electronic Structure ◽

Band Gap ◽

Ground State ◽

Density Functional ◽

Singlet Ground State ◽

Intermediate Valence ◽

Kondo Insulator ◽

The Density Functional Theory ◽

Indirect Band Gap ◽

The Moment

ABSTRACT The electronic structure of PuB6, an actinide analog of SmB6 , was investigated making use of a combination of the density functional theory (DFT), and the exact diagonalization (ED) of an effective discrete Anderson impurity model. Intermediate valence ground state with the f-shell occupation n4f =5.5 for the Pu atom in PuB6 is calculated. The 5f-shell magnetic moment is completely compensated by the moment carried by the electrons in the conduction band. Already in DFT, PuB6 is an insulator with a small amount of holes near the X-point, and the indirect band gap of ≈60 meV. This band gap becomes direct in DFT+ED calculations supporting the idea of “topological Kondo insulator” in PuB6. Connection between the electronic structure of PuB6 and δ-Pu is established. We propose that these materials belong to a new class of intermediate valence “Racah” materials with the multi-orbital “Kondo-like” singlet ground-state.

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Electronic structure of nitrogen-vacancy doped SmN: Intermediate valence and 4f transport in a ferromagnetic semiconductor

Physical Review B ◽

10.1103/physrevb.104.075124 ◽

2021 ◽

Vol 104 (7) ◽

Author(s):

W. F. Holmes-Hewett

Keyword(s):

Electronic Structure ◽

Ferromagnetic Semiconductor ◽

Nitrogen Vacancy ◽

Intermediate Valence

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EELS Measurement of the Local Electronic Structure of Copper Atoms Segregated to Aluminum Grain Boundaries

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164179 ◽

1996 ◽

Vol 54 ◽

pp. 342-343

Author(s):

S.J. Splinter ◽

J. Bruley ◽

P.E. Batson ◽

D.A. Smith ◽

R. Rosenberg

Keyword(s):

Electronic Structure ◽

Grain Boundaries ◽

Boundary Segregation ◽

Thin Layers ◽

Nominal Composition ◽

Spatially Resolved ◽

Service Lifetime ◽

Heat Treated ◽

Probe Size ◽

Local Electronic Structure

It has long been known that the addition of Cu to Al interconnects improves the resistance to electromigration failure. It is generally accepted that this improvement is the result of Cu segregation to Al grain boundaries. The exact mechanism by which segregated Cu increases service lifetime is not understood, although it has been suggested that the formation of thin layers of θ-CuA12 (or some metastable substoichiometric precursor, θ’ or θ”) at the boundaries may be necessary. This paper reports measurements of the local electronic structure of Cu atoms segregated to Al grain boundaries using spatially resolved EELS in a UHV STEM. It is shown that segregated Cu exists in a chemical environment similar to that of Cu atoms in bulk θ-phase precipitates.Films of 100 nm thickness and nominal composition Al-2.5wt%Cu were deposited by sputtering from alloy targets onto NaCl substrates. The samples were solution heat treated at 748K for 30 min and aged at 523K for 4 h to promote equilibrium grain boundary segregation. EELS measurements were made using a Gatan 666 PEELS spectrometer interfaced to a VG HB501 STEM operating at 100 keV. The probe size was estimated to be 1 nm FWHM. Grain boundaries with the narrowest projected width were chosen for analysis. EDX measurements of Cu segregation were made using a VG HB603 STEM.

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