A Study of the Electronic Structure of Rare Earth Hexaborides

Grushko, Yu. S.; Paderno, Yu. B.; Mishin, K. Ya.; Molkanov, L. I.; Shadrina, G. A.; Konovalova, E.S.; Dudnik, E. M.

doi:10.1002/pssb.2221280225

Cited by 21 publications

(15 citation statements)

References 9 publications

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“…5). This shift is obviously due to the higher carrier concentration in metallic LaB , which after Grushko et al (10) exceeds that in semiconducting EuB and YbB by about two orders of magnitude.…”

Section: Discussion (A) Phononsmentioning

confidence: 94%

Interband Transitions, IR-Active Phonons, and Plasma Vibrations of Some Metal Hexaborides

Werheit¹,

Au²,

Schmechel³

et al. 2000

Journal of Solid State Chemistry

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Section: Discussion (A) Phononsmentioning

confidence: 94%

Interband Transitions, IR-Active Phonons, and Plasma Vibrations of Some Metal Hexaborides

Werheit¹,

Au²,

Schmechel³

et al. 2000

Journal of Solid State Chemistry

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“…Here we report inelastic neutron scattering (INS) experiments that reveal a resonant mode with identical characteristics in the non-superconducting heavy-fermion metal CeB 6 , which has been intensely investigated because of its intriguing phase behavior [11][12][13] on the background of an exceptionally simple crystal structure and chemical composition. The electronic states near the Fermi level of CeB 6 are composed of localized cerium-4 f 1 levels hybridized with itinerant cerium-5d and boron-2p electrons, 18,19 closely analogous to those of the superconductors CeCoIn 5 and CeCu 2 Si 2 , where prominent resonant modes have been reported. 4,6 In contrast to these superconducting compounds, however, CeB 6 exhibits AFM order below T N = 2.3 K. 20 The AFM transition is preceded by another phase transition at T Q = 3.2 K, whose order parameter has long remained "hidden" to standard experimental probes such as neutron diffraction.…”

mentioning

confidence: 88%

Resonant magnetic exciton mode in the heavy-fermion antiferromagnet CeB6

et al. 2012

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Resonant magnetic excitations are recognised as hallmarks of unconventional superconductivity in copper oxides, iron pnictides and heavy-fermion compounds. model calculations have related these modes to the microscopic properties of the pair wave function, but the mechanisms of their formation are still debated. Here we report the discovery of a similar resonant mode in the non-superconducting antiferromagnetic heavy-fermion metal CeB 6 . unlike conventional magnons, the mode is non-dispersive and is sharply peaked around a wave vector separate from those characterising the antiferromagnetic order. It is likely associated with a co-existing order parameter of the unusual antiferro-quadrupolar phase of CeB 6 , which has long remained hidden to neutron-scattering probes. The mode energy increases continuously below the onset temperature for antiferromagnetism, in parallel to the opening of a nearly isotropic spin gap throughout the Brillouin zone. These attributes are similar to those of the resonant modes in unconventional superconductors. This unexpected commonality between the two disparate ground states indicates the dominance of itinerant spin dynamics in the ordered lowtemperature phases of CeB 6 and throws new light on the interplay between antiferromagnetism, superconductivity and 'hidden' order parameters in correlated-electron materials.

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“…This behavior is typical for the interacting electrons in the conduction band, which is filled in CeB 6 by hybridized 5d electrons of cerium 3 and 2p electrons of boron according to the band calculations. 26,27 At definite conditions, these interaction can be stronger than those between the moments of localized 4 f electrons, and as a result the antiferromagnetic fluctuations of itinerant electrons may appear at T >> T N (Remind that in our case the antiferromagnetic fluctuations arise at T ≈ 3T N ).…”

Section: +mentioning

confidence: 99%

“…3 While 4f system is studied in detail, magnetic interactions among 5d electrons have never been observed. We present in this communication indications of 5d−electrons itinerant magnetism.…”

Section: +mentioning

confidence: 99%

Itinerant magnetism in the Kondo crystalCeB6as indicated by polarized neutron scattering

et al. 2005

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A magnetic Bragg reflection corresponding to the wave vector k 13 = (2π/a)[1/2,1/2,1/2] of the antiferroquadrupolar ordering is found in CeB 6 in zero magnetic field below the Néel temperature T N . Its intensity is two orders of magnitude weaker than those due to the basic magnetic structure [O. Zaharko et al., Phys. Rev. B 68, 214401 (2003)]. The peak has a width of the other Bragg reflections below T N , but widens abruptly at T = T N with simultaneous increase of intensity. Correlation length just above T N is of the order of 70 Å. The peak intensity decreases to zero at T ≈ 7 K with no visible anomaly at the antiferro-quadrupolar ordering temperature T Q = 3.3 K. The studies of the heavy-fermion Kondo-lattice system, CeB 6 had started more than 30 years ago, 1 but its highly unusual properties are being still extensively debated. Cerium hexaboride crystallizes in the CaB 6 − structure (space group Pm3m) with a B 6 molecule in the form of a regular octahedron and the Ce ion situated, respectively, at the corner and at the center of the simple cubic unit cell with a = 4.141 Å).1 A theoretical study of CaB 6 − type materials 2 indicates that each B 6 octahedron requires 2 electrons from Ce to stabilize a 3D boron network. Two electrons are left on Ce 3+, 4f and 5d. 3 While 4f system is studied in detail, magnetic interactions among 5d electrons have never been observed. We present in this communication indications of 5d−electrons itinerant magnetism.It has been established that the crystalline electric field of the cubic boron environment splits the Ce 3+ multiplet 4f 1 into a ground-state quartet Γ 8 and a doublet Γ 7 with a gap of 47 meV. 4 At the temperature range of interest (T < ~7 K) one can neglect admixture of excited level. The resistivity grows logarithmically, attaining its maximum at T ≈ 3.2 K. 5The Kondo temperature was estimated as T K ≈ 8 K, 6 but then it was revised down to T K ≈ 1 K on the basis of magnetic susceptibility data. 7 The phase diagram in this region is very unusual. Two specific heat aomalies were observed at about 3.3 K and 2.4 K in the absence of external magnetic field. 8 The results of a zero-field neutron diffraction experiment, 11 . This observation was explained by an ordering of the quadrupolar moments Q and -Q at T Q = 3.3 K, which would split the ground-state quartet Γ 8 into two doublets. Due to the quadrupolar ordering, the external magnetic field would induce antiferromagnetic spin arrangement with the same wave vector k 13 . All these results indicated the existence of three phases: the non-ordered paramagnetic phase I ( T Q < T), the antiferro-quadrupolar (AFQ) phase II ( T N

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A Study of the Electronic Structure of Rare Earth Hexaborides

Cited by 21 publications

References 9 publications

Interband Transitions, IR-Active Phonons, and Plasma Vibrations of Some Metal Hexaborides

Interband Transitions, IR-Active Phonons, and Plasma Vibrations of Some Metal Hexaborides

Resonant magnetic exciton mode in the heavy-fermion antiferromagnet CeB6

Itinerant magnetism in the Kondo crystalCeB6as indicated by polarized neutron scattering

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