Evidence of pseudogap formation in a new valence-fluctuating compound: CeRhSb

Malik, S.K.; Adroja, D. T.

doi:10.1103/physrevb.43.6277

Cited by 210 publications

(112 citation statements)

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“…Most CeTX compounds show antiferromagnetic ordering at low temperature but also a few ferromagnets have been observed. Very detailed studies were performed for the valence fluctuating compounds, e. g. CeRhGa [1], CeNiIn [2], CeRhIn [3], CeRhSn [4], or CeRhSb [5]. These intermetallics have only one crystallographic cerium site, leading to non-integer cerium valences over the whole temperature range.…”

Section: Introductionmentioning

confidence: 99%

The Solid Solutions (Ce_1-xLa_x)RuSn

Niehaus

Chevalier

Abdala

et al. 2013

Zeitschrift Für Naturforschung B

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X-Ray-pure samples of the solid solutions (Ce 1−x La x )RuSn were obtained up to x = 0.5. Powder diffraction data show the CeRuSn-type superstructure up to x ≈ 0.3 and the CeCoAl-type subcell for higher lanthanum contents. The structure of a single crystal with x = 0.5 was refined on the basis of single-crystal X-ray diffractometer data: CeCoAl type, C2/m, a = 1160.8(2), b = 477.6(1), c = 511.6(1) pm, β = 102.97(2) • , wR = 0.0510, 444 F 2 values, 20 variables. Magnetic investigations were performed for all samples up to a lanthanum content of x = 0.4. No cooperative phenomena could be observed, and all samples show Curie-Weiss behavior above a certain temperature. The cerium valence is about 3.32(2) for all samples of the solid solution. Hence, La 3+ has to replace Ce 3+ as well as Ce 4+ in a particular quantity. The electrical resistivity measurements confirm the suppression of the magnetic ordering and the structural transition upon replacement of cerium by lanthanum. 119 Sn Mössbauer spectra of samples with x = 0.2 and 0.5 are indicative of single tin sites with isomer shifts of δ = 1.86(1) mm s −1 for x = 0.2 and δ = 1.88(1) mm s −1 for x = 0.5. Both signals are subject to significant quadrupole splitting, a consequence of the low site symmetry. Results of XANES measurements are perfectly in line with the cerium valences determined by susceptibility measurements and yield a constant value of 3.16(1) for all investigated compounds.

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Section: Introductionmentioning

confidence: 99%

The Solid Solutions (Ce_1-xLa_x)RuSn

Niehaus

Chevalier

Abdala

et al. 2013

Zeitschrift Für Naturforschung B

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“…Following extensive experimental (59) work on CeNiSn [8], CeRhSb [9], and Ce 3 Βi4 Pd3 [10], the. term "Kondo insulator" is attributed to an intermetallic compound which: has a nonmagnetic ground state, has an insulating gap due to many-body interactions between conduction and localized electrons in the f shell, and has low-lying excitation which exhibits properties of strong correlation.…”

Section: Introductionmentioning

confidence: 99%

Band Gap Stability in Kondo Insulators

2000

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We report on magnetic measurements and electronic structure investigations of CeNiSn and CeRhSb. Both belong to the group of Kondo insulators. The magnetic susceptibility shows the nonmagnetic ground state for these compounds and their alloys. The 3d X-ray photoemission spectroscopy spectra show evidence for the mixed valence state of Ce in CeRhSb alloys, as also seen for CeNiSn, whereas the spectra for the La substituted (Ce,La)NiSn compounds show only evidence for a pure Ce 3+ ground state. We suggest the presence of Kondo-hole states in (Ce,La)RhSb. The location of the pseudogap in CeRhSb varies with the number of free electron, the valence of Ce, and the f-d hybridization. We discuss the similar crystallographic properties and the closed electronic structures of ZrNiSn-type semi-Heusler alloys and CeNiSn-type Kondo insulators.

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“…It is interesting to note that despite the spin gap opening at 45 K, CeOs 2 Al 10 exhibits long-range magnetic ordering below 29 K. Thus CeOs 2 Al 10 is a unique system and probably the first Ce-based system exhibiting a Kondo insulating gap and long-range magnetic ordering. All Kondo insulators known so far, such as CeNiSn, CeRhSb, Ce 3 Pt 3 Bi 4 , SmB 6 , YbB 6 and FeSi, are paramagnetic and do not exhibit long-range magnetic ordering down to the lowest measured temperature [20][21][22][23][24]. Furthermore in the proposed phase diagram of Fig.2, the majority of Kondo insulators are in the non-magnetic heavy fermion and mixed valence regimes of the phase diagram, but CeT 2 Al 10 (T=Ru and Os) are on the magnetic side.…”

Section: Ins Study On Polycrystalline Cet 2 a L0mentioning

confidence: 99%

“…As a consequence of strong c-f hybridization and the formation of a Kondo singlet ground state, the Kondo insulating ground state is not compatible with magnetic ordering. For example, Kondo insulators CeNiSn [20], CeRhSb [21], Ce 3 Pt 3 Bi 4 [22], SmB 6 [13,23] and YbB 12 [24] remain paramagnetic and no long range magnetic ordering has been observed in these systems. Theoretical models were proposed to explain the anisotropic properties of CeNiSn by Ikeda and Miyake (IM) based on anisotropic hybridization in k-space [25], and by Moreno and Coleman (MC) based on global and local minima in the crystal field (CEF) parameter space to explain a gap anisotropy [26].…”

Section: Introductionmentioning

confidence: 99%

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Adroja¹,

Muro²,

Takabatake³

et al. 2016

SSP

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Abstract. The recent discovery of topological Kondo insulating behaviour in strongly correlated electron systems has generated considerable interest in Kondo insulators both experimentally and theoretically. The Kondo semiconductors CeT 2 Al 10 (T=Fe, Ru and Os) possessing a c-f hybridization gap have received considerable attention recently because of the unexpected high magnetic ordering temperature of CeRu 2 Al 10 (T N =27 K) and CeOs 2 Al 10 (T N =28.5 K) and the Kondo insulating behaviour observed in the valence fluctuating compound CeFe 2 Al 10 with a paramagnetic ground state down to 50 mK. We are investigating this family of compounds, both in polycrystalline and single crystal form, using inelastic neutron scattering to understand the role of anisotropic c-f hybridization on the spin gap formation as well as on their magnetic properties. We have observed a clear sign of a spin gap in all three compounds from our polycrystalline study as well as the existence of a spin gap above the magnetic ordering temperature in T=Ru and Os. Our inelastic neutron scattering studies on single crystals of CeRu 2 Al 10 and CeOs 2 Al 10 revealed dispersive gapped spin wave excitations below T N . Analysis of the spin wave spectrum reveals the presence of strong anisotropic exchange, along the c-axis (or z-axis) stronger than in the ab-plane. These anisotropic exchange interactions force the magnetic moment to align along the c-axis, competing with the single ion crystal field anisotropy, which prefers moments along the a-axis. In the paramagnetic state (below 50 K) of the Kondo insulator CeFe 2 Al 10 , we have also observed dispersive gapped magnetic excitations which transform into quasi-elastic scattering on heating to 100 K. We will discuss the origin of the anisotropic hybridization gap in CeFe 2 Al 10 based on theoretical models of heavy-fermion semiconductors.

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Evidence of pseudogap formation in a new valence-fluctuating compound: CeRhSb

Abstract: The compound CeRhSb, crystallizing in the orthorhombic CeCu2-type structure, has been synthesized. Its unit-cell volume is anomalous in relation to that of isostructural RRhSb (R =rare earth) compounds.Its magnetic susceptibility is weakly temperature dependent and exhibits a

Cited by 210 publications

References 21 publications

The Solid Solutions (Ce_1-xLa_x)RuSn

The Solid Solutions (Ce_1-xLa_x)RuSn

Band Gap Stability in Kondo Insulators

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Evidence of pseudogap formation in a new valence-fluctuating compound: CeRhSb

Abstract: The compound CeRhSb, crystallizing in the orthorhombic CeCu2-type structure, has been synthesized. Its unit-cell volume is anomalous in relation to that of isostructural RRhSb (R =rare earth) compounds.Its magnetic susceptibility is weakly temperature dependent and exhibits a

Cited by 210 publications

References 21 publications

The Solid Solutions (Ce1-xLax)RuSn

The Solid Solutions (Ce1-xLax)RuSn

Band Gap Stability in Kondo Insulators

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The Solid Solutions (Ce_1-xLa_x)RuSn

The Solid Solutions (Ce_1-xLa_x)RuSn