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1
Content available remote Electronic structure of CePdAl; experiment and calculations
Głogowski W., Goraus J., Ślebarski A.
Materials Science Poland
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2008
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Vol. 26, No. 3
729--734
EN
CePdAl exhibits an antiferromagnetic phase below TN = 2.7 K; its physical properties are typical of heavy fermion compounds (specific heat coefficient γ= C/T = 270 mJ/(mol�EK2)). The triangular coordination symmetry of the magnetic Ce ions gives rise to geometrical frustration and leads to an incommensurate antiferromagnetic structure below TN, showing a coexistence of ordered and frustrated Ce moments. The purpose of this work was to discuss electronic structure of CePdAl and its influence on the geometrical frustration in the Kagome-like lattice and the Kondo effect in CePdAl. We present the results of the X-ray diffraction analysis and the XPS Ce 3d core and valence band spectra. We also present the spinpolarized band structure calculations for CePdAl, using the LAPW method.
2
Content available remote Electronic structure of Fe2VGa
Goraus J., Ślebarski A.
Materials Science Poland
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2007
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Vol. 25, No. 2
359--362
EN
We present the band structure calculations on the Heusler alloy Fe2VGa which shows a pseudogap at the Fermi level. The compound is found to be nonmagnetic. We observed, however, that an atomic disorder which has been experimentally observed can lead to the behaviour characteristic of the heavy-Fermion compounds. The antisite Fe defects locate the d states forming a narrow d-band at the Fermi level.
3
Content available remote Electronic structure of CeRh2Sn4
Gamża M., Schnelle W., Ślebarski A., Rosner H.
Materials Science Poland
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2007
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Vol. 25, No. 2
269--274
EN
We performed a study of the compound CeRh2Sn4, not investigated so far. Our samples were carefully characterized by X-ray powder diffraction analysis and by locally resolved, energy dispersive X-ray spectroscopy (EDXS). We present a combined experimental and theoretical study based on X-ray photoelectron spectroscopy (XPS) data together with ab initio band structure calculations. The Ce 3d XPS spectrum indicates a small mixed valence of Ce. Analysis of the 3d94f 2 weight using the Gunnarsson-Schönhammer theory suggests a hybridization between Ce 4f states and the conduction band of about 85 meV. The valence band spectrum, dominated by Rh 4d states, is in a very good agreement with the calculated one.
4
Content available remote Photoemission study of CeRh(1-x)PdxAl. The effect of Pd doping on the electronic structure
Głogowski W., Ślebarski A.
Materials Science Poland
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2006
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Vol. 24, No. 3
551--555
EN
In view of a contrasting behaviour of Pd-containing and Rh-containing systems, we investigate solid solutions CeRh1-xPdxAl in order to determine the dependence of their electronic properties on the number of the conduction electrons. We present structural and X-ray photoemission spectroscopy (XPS) data for CeRh1-xPdxAl. We also discuss the influence of the number of free electrons in the conduction band on the stability of the crystallographic structure and the occupation number of the f-shell.
5
Content available remote Electronic structure of CeRhIn5 and CeIrIn5
Gamża M., Ślebarski A., Deniszczyk J.
Materials Science Poland
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2006
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Vol. 24, No. 3
569--576
EN
We have performed Full Potential Linearized Augmented Plane-Wave (FP-LAPW) calculations of the layered cerium compounds CeRhIn5 and CeIrIn5, which belong to the new, intensively investigated family of heavy fermion (HF) materials. The ground states of this compounds can be tuned between antiferromagnetism (AFM) and superconductivity (SC) by external pressure or doping. We have carried out x-ray photoelectron spectroscopy (XPS) experiments to compare measured valence band spectra with theoretical calculations. We also analyse the XPS 3d Ce spectra, to estimate the occupation of the Ce 4f shell and the hybridization between 4f and conduction electrons. We have found and discussed an influence of the lattice parameter a and the d-f interatomic hybridization effect on the ground state properties in the series of CeMIn5 compounds.
6
Content available remote Electronic structure of Ce2Rh3Al9
Goraus J., Ślebarski A., Deniszczyk J.
Materials Science Poland
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2006
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Vol. 24, No. 3
563--568
EN
We have investigated the XPS spectra of Ce2Rh3Al9 compound and calculated DOS by using the FP-LAPW (Full Potential Linear Augmented Plane Wave) and TB-LMTO-ASA (Tight Binding Linear Muffin Tin Orbitals) methods. The overall agreement between the calculated and the measured XPS valence band spectra is good. Analysis of the 3d XPS (X-ray Photoemission) spectra, using the Gunnarson-Schonhammer theory, suggests a mixed valence behaviour of Ce. FP-LAPW calculations show a half-metallic behaviour of Ce2Rh3Al9, whereas from LMTO calculations results a semiconducting and nonmagnetic ground state. This result is, however, in contradiction to the resistivity (T) experimental observation, which has not shown an activated behaviour. We attribute a possible appearance of the semiconducting/halfmetallic gap for Ce2Rh3Al9 to an atomic disorder.
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