Filled skutterudite CeFe<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>4</mml:mn></mml:msub></mml:math>As<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>12</mml:mn></mml:msub></mml:math>: Disclosure of a semiconducting state

Wawryk, R.; Henkie, Z.; Pietraszko, A.; Cichorek, T.; Kępiński, Leszek; Jezierski, A.; Kaczkowski, J.; Baumbach, Ryan; Maple, M. B.

doi:10.1103/physrevb.84.165109

Cited by 16 publications

(13 citation statements)

References 49 publications

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“…Previous studies have shown a semiconducting ground state in all the Ce-filled arsenide skutterudites [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…However, it turned out that low-temperature properties of CeFe 4 As 12 and CeRu 4 As 12 are strongly sample dependent: For the latter system, polycrystalline samples display semiconducting behavior with an energy gap of 50 K, [8] while single crystals have a metallic ground state and exhibit non-Fermi-liquid behavior [9]. specimens [10]. Contrary to these systems, an increase of the electrical resistivity of CeOs 4 As 12 by two orders of magnitude upon cooling below about 135 K is robust against sample variation [11].…”

Section: Introductionmentioning

confidence: 99%

“…This applies to the properties of the phosphide and antimonide skutterudites, as well. Indeed, CeOs 4 As 12 [11], CeRu 4 As 12 [8,9], and CeFe 4 As 12 [10] become semiconductors at low temperatures with the highest thermoelectric power observed for CeFe 4 As 12 . The latter observation is for a sample that has off-stoichiometry defects of order 10 20 cm -3 with a maximum thermoelectric power +86 V/K at 120 K. The Ce and U iron phosphides filled skutterudites, CeFe 4 P 12 and UFe 4 P 12 , were also found to be semiconductors.…”

Section: Introductionmentioning

confidence: 99%

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Electron transport and magnetic properties of the filled skutterudite compound ThFe4As12

Wawryk

Żogał

Rudenko

et al. 2016

Journal of Alloys and Compounds

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Single crystals of the filled skutterudite compound ThFe 4 As 12 were examined down to T = 0.4 K and in magnetic fields up to B = 9 T. Electron transport properties combined with results of Hall-effect measurements indicate semimetallic properties with a charge carrier density of the order of 2 × 10 20 cm-3. In terms of a two-band model, the effective mass of the electrons is nearly a factor of 5 larger than the hole effective mass. A small carrier density is in line with the lack of magnetic ordering in this Fe-based filled skutterudite. Therefore, a Sommerfeld coefficient of the electronic specific heat of 45 mJmol-1 K-2 for semimetallic ThFe 4 As 12 is an unexpected observation whose origin remains to be explained.

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“…Previous studies have shown a semiconducting ground state in all the Ce-filled arsenide skutterudites [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electron transport and magnetic properties of the filled skutterudite compound ThFe4As12

Wawryk

Żogał

Rudenko

et al. 2016

Journal of Alloys and Compounds

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“…3,7 Moreover, their Seebeck coefficient, S, is sometimes enhanced, owing to the strong hybridization between the conduction electron and f-electron states. [7][8][9][10] Consequently, these materials have good thermoelectric properties, parametrized by a high value of the figure of merit, ZT = T S 2 σe κtot . Unlike typical metals, S can be large and the ratio T σ e /κ tot is not approximately constant.…”

Section: Introductionmentioning

confidence: 99%

“…3,7 As such, the cerium-arsenide compounds have properties that are intermediate between the cerium-phosphide and the cerium-antimonide analogues. While CeFe 4 As 12 exhibits semimetallic and semiconductor behavior that is finely tuned by morphology and charge carrier concentration, 10 CeRu 4 As 12 shows evidence for strong electronic correlations and non-Fermiliquid behavior. 8 In contrast, CeOs 4 As 12 is a hybridization gap insulator with a gap size that is intermediate between those of CeOs 4 P 12 and CeOs 4 Sb 12 .…”

Section: Introductionmentioning

confidence: 99%

Complex vibrations in arsenide skutterudites and oxyskutterudites

et al. 2015

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The local structure of two skutterudite families -CeM4As12 (M = Fe, Ru, Os) and LnCu3Ru4O12 (Ln = La, Pr, and Nd) -have been studied using the Extended X-Ray Absorption Fine Structure (EXAFS) technique with a focus on the lattice vibrations about the rare earth "rattler atoms", and the extent to which these vibrations can be considered local modes, with the rattler vibrating inside a nearly rigid cage. X-ray absorption data at all the metal edges were collected over a temperature range of 4 to 300 K and analyzed using standard procedures. The pair-distances from EXAFS results agree quite well with the average structure obtained from diffraction. The cage structure is formed by the M and As atoms in CeM4As12 and by Cu, O, and Ru atoms in LnCu3Ru4O12. Although some of the bonds within the cage are quite stiff (Correlated Debye temperatures, θcD, are ∼ 500 K for CeM4As12 and above 800 K for LnCu3Ru4O12) we show the structure is not completely rigid. For the rattler atom the nearest neighbor pairs have a relatively low Einstein temperature, θE; ∼ 100-120 K for Ce-As and ∼ 130 K for Ln-O. Surprisingly, the behavior of the second neighbor pairs are quite different; for CeM4As12 the second neighbor pairs (Ce-M have a weaker bond while for LnCu3Ru4O12 the Ln-Ru second neighbor pair has a stiffer effective spring constant than the first neighbor pair. In addition, we show that the As4 or CuO4 rings are relatively rigid units and that their vibrations are anisotropic within these cubic structures, with stiff restoring forces perpendicular to the rings and much weaker restoring forces in directions parallel to the rings. Consequently vibrations of the rings may also act as "rattlers" and help suppress thermal conductivity. In general neither the rigid cage approximation nor the simple reduced mass approximation are sufficient for describing rattler behavior.

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Indications of a magnetic‐field‐driven anisotropy in the hybridization gap semiconductor CeOs₄As₁₂

Cichorek

Bochenek

Wawryk

et al. 2013

Physica Status Solidi (b)

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The filled skutterudite compound CeOs 4 As 12 displays phenomena that are associated with hybridization between the 4felectron and conduction-electron states. This holds especially true for a semiconducting ground state with a main energy gap as small as D/k B ¼ 45 K. When subjected to magnetic field, the hybridization gap semiconductor CeOs 4 As 12 becomes metallic below around 2.5 K. Preliminary electrical-resistivity experiments provide evidence for an anisotropy of magnetic-fieldinduced insulator-metal transition in this cubic material. Our findings suggest a contribution of the quartet 4f-G À 67 states to transport properties of CeOs 4 As 12 .

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Filled skutterudite CeFe4As12: Disclosure of a semiconducting state

Cited by 16 publications

References 49 publications

Electron transport and magnetic properties of the filled skutterudite compound ThFe4As12

Electron transport and magnetic properties of the filled skutterudite compound ThFe4As12

Complex vibrations in arsenide skutterudites and oxyskutterudites

Indications of a magnetic‐field‐driven anisotropy in the hybridization gap semiconductor CeOs₄As₁₂

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Filled skutterudite CeFe4As12: Disclosure of a semiconducting state

Cited by 16 publications

References 49 publications

Electron transport and magnetic properties of the filled skutterudite compound ThFe4As12

Electron transport and magnetic properties of the filled skutterudite compound ThFe4As12

Complex vibrations in arsenide skutterudites and oxyskutterudites

Indications of a magnetic‐field‐driven anisotropy in the hybridization gap semiconductor CeOs4As12

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Product

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Indications of a magnetic‐field‐driven anisotropy in the hybridization gap semiconductor CeOs₄As₁₂