New universality class of quantum criticality in Ce- and Yb-based heavy fermions

Watanabe, Shinji; Miyake, Kazumasa

doi:10.1088/0953-8984/24/29/294208

Cited by 27 publications

(27 citation statements)

References 79 publications

(249 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nevertheless, only a few ARPES works have been reported for the renormalized (heavy) bands of HF systems [12,13,21]. The lack of microscopic experimental information makes it difficult to reveal the origin of the quantum criticality for realistic HF systems, which is proposed on the basis of several models due to the spin fluctuation [25], Kondo breakdown [26][27][28], and valence fluctuation theories [29,30]. The HF phenomena are complicated by the strong momentum dependence of a HF nature arising from anisotropic cf hybridizations, which reflect the 4f charge distributions as clearly revealed by soft x-ray absorption spectroscopy [31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Evidence for momentum-dependent heavy-fermionic electronic structures: Soft x-ray ARPES for the superconductor CeNi2Ge2 in the normal state

et al. 2018

View full text Add to dashboard Cite

We present clear experimental evidence for the momentum-dependent heavy fermionic electronic structures of the 4f -based strongly correlated system CeNi 2 Ge 2 by soft x-ray angle-resolved photoemission spectroscopy. A comparison between the experimental three-dimensional quasiparticle dispersion of LaNi 2 Ge 2 and CeNi 2 Ge 2 has revealed that heavy fermionic electronic structures are seen in the region surrounding a specific momentum. Furthermore, the wave vectors between the observed "heavy spots" are consistent with a result of neutron scattering reflecting magnetic correlations, which could be a trigger for the superconductivity in CeNi 2 Ge 2 .

show abstract

Section: Introductionmentioning

confidence: 99%

Evidence for momentum-dependent heavy-fermionic electronic structures: Soft x-ray ARPES for the superconductor CeNi2Ge2 in the normal state

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Emergence of almost flat mode is considered to be ascribed to strong local correlation effect by U = ∞. 6,19,20) The reason why the charge-transfer mode between the 3rd and 4th shells is extraordinary enhanced [see the (i, ξ) = (1, 13) data in Fig. 3] is due to the strongest f-c hybridization, |V 3−4 | > |V 2−3 |, |V 3−5 |, arising from the shortest Yb-Al distance and existence of the DOS around ε F [see A cc ξξ (ε F ) for ξ = 13 in Fig.…”

mentioning

confidence: 99%

Origin of Quantum Criticality in Yb–Al–Au Approximant Crystal and Quasicrystal

Watanabe

Miyake

2016

J. Phys. Soc. Jpn.

Self Cite

View full text Add to dashboard Cite

To get insight into the mechanism of emergence of unconventional quantum criticality observed in quasicrystal Yb 15 Al 34 Au 51 , the approximant crystal Yb 14 Al 35 Au 51 is analyzed theoretically. By constructing a minimal model for the approximant crystal, the heavy quasiparticle band is shown to emerge near the Fermi level because of strong correlation of 4f electrons at Yb. We find that charge-transfer mode between 4f electron at Yb on the 3rd shell and 3p electron at Al on the 4th shell in Tsai-type cluster is considerably enhanced with almost flat momentum dependence.The mode-coupling theory shows that magnetic as well as valence susceptibility exhibits χ ∼ T −0.5 for zero-field limit and is expressed as a single scaling function of the ratio of temperature to magnetic field T/B over four decades even in the approximant crystal when some condition is satisfied by varying parameters, e.g., by applying pressure. The key origin is clarified to be due to the strong locality of the critical Yb-valence fluctuation and small Brillouin zone reflecting the large unit cell, giving rise to the extremely-small characteristic energy scale. This also gives a natural explanation for the quantum criticality in the quasicrystal corresponding to the infinite limit of the unit-cell size.Recent discovery of unconventional quantum critical phenomena in quasicrystal Yb 15 Al 34 Au 51 has attracted much attention.1, 2) The measured criticality such as magnetic susceptibility χ ∼ T −0.5 , NMR relaxation rate (T 1 T ) −1 ∼ T −0.5 , specific heat C e /T ∼ − log T , and resistivity ρ ∼ T is unconventional and quite similar to those observed in periodic crystals such as heavy-electron metals YbRh 2 Si 2 3) and β-YbAlB 4 , 4,5) which are well explained by quantum critical phenomena of Yb-valence fluctuations.6)The quasicrystal Yb 15 Al 34 Au 51 is constituted of concentric shell structures of Tsai-type cluster shown in Fig. 1. 1, 7) There also exists approximant crystal Yb 14 Al 35 Au 51 .7) The approximant crystal has periodic arrangement of the body-centered cubic (bcc) structure whose unit cell contains shell structures shown in Figs. 1(a)-1(e). Theoretical analysis of the Yb-AlAu cluster taking account of critical Yb-valence fluctuations has provided a natural explanation for robustness of quantum criticality in the quasicrystal measured under pressure and has pointed out a possibility that the same criticality appears even in the approximant crystal when pressure is applied. 8,9) On the other hand, a new theoretical framework for critical Yb-valence fluctuation under magnetic field has been developed recently.10) The theory has succeeded in explaining novel scaling discovered in β-YbAlB 4 where the magnetic susceptibility χ is expressed as a single scaling function of the ratio of temperature to magnetic field T/B over four decades. 5)Surprisingly, recent measurement of magnetic susceptibility in the quasicrystal Yb 15 Al 34 Au 51 has revealed that the same T/B-scaling behavior appears over six decades of T/B.11) This strongly s...

show abstract

“…A comparable situation can be found in CeFe 2 Al 10 in which the confluence of the two types of magnetic species has the surprising effect of producing the nonmagnetic Kondo insulating state [29], which is an extreme case of local-moment hybridization with the conduction electrons. Recently, there has been a resurgence of research activities in intermediate valence systems following the discovery of superconductivity and quantum critical behavior in an intermediate valence (IV) heavy fermion β-YbAlB 4 [10,[30][31][32][33][34][35][36][37].…”

mentioning

confidence: 99%

Contiguous3dand4fMagnetism: Strongly Correlated3dElectrons in
Khuntia
¹
,
Peratheepan
²
,
Strydom
³

et al. 2014
Phys. Rev. Lett.
17
0
7
1
View full text Add to dashboard Cite

We present magnetization, specific heat, and (27)Al NMR investigations on YbFe2Al10 over a wide range in temperature and magnetic field. The magnetic susceptibility at low temperatures is strongly enhanced at weak magnetic fields, accompanied by a ln(T0/T) divergence of the low-T specific heat coefficient in zero field, which indicates a ground state of correlated electrons. From our hard-x-ray photoemission spectroscopy study, the Yb valence at 50 K is evaluated to be 2.38. The system displays valence fluctuating behavior in the low to intermediate temperature range, whereas above 400 K, Yb(3+) carries a full and stable moment, and Fe carries a moment of about 3.1 μB. The enhanced value of the Sommerfeld-Wilson ratio and the dynamic scaling of the spin-lattice relaxation rate divided by T[(27)(1/T1T)] with static susceptibility suggests admixed ferromagnetic correlations. (27)(1/T1T) simultaneously tracks the valence fluctuations from the 4f Yb ions in the high temperature range and field dependent antiferromagnetic correlations among partially Kondo screened Fe 3d moments at low temperature; the latter evolve out of an Yb 4f admixed conduction band.

show abstract

New universality class of quantum criticality in Ce- and Yb-based heavy fermions

Cited by 27 publications

References 79 publications

Evidence for momentum-dependent heavy-fermionic electronic structures: Soft x-ray ARPES for the superconductor CeNi2Ge2 in the normal state

Evidence for momentum-dependent heavy-fermionic electronic structures: Soft x-ray ARPES for the superconductor CeNi2Ge2 in the normal state

Origin of Quantum Criticality in Yb–Al–Au Approximant Crystal and Quasicrystal

Contiguous3dand4fMagnetism: Strongly Correlated3dElectrons in
Khuntia
¹
,
Peratheepan
²
,
Strydom
³

et al. 2014
Phys. Rev. Lett.
17
0
7
1
View full text Add to dashboard Cite

Contact Info

Product

Resources

About

New universality class of quantum criticality in Ce- and Yb-based heavy fermions

Cited by 27 publications

References 79 publications

Evidence for momentum-dependent heavy-fermionic electronic structures: Soft x-ray ARPES for the superconductor CeNi2Ge2 in the normal state

Evidence for momentum-dependent heavy-fermionic electronic structures: Soft x-ray ARPES for the superconductor CeNi2Ge2 in the normal state

Origin of Quantum Criticality in Yb–Al–Au Approximant Crystal and Quasicrystal

Contiguous3dand4fMagnetism: Strongly Correlated3dElectrons inKhuntia1, Peratheepan2, Strydom3 et al. 2014Phys. Rev. Lett.17071View full textAdd to dashboardCite

Contact Info

Product

Resources

About

Contiguous3dand4fMagnetism: Strongly Correlated3dElectrons in
Khuntia
¹
,
Peratheepan
²
,
Strydom
³

et al. 2014
Phys. Rev. Lett.
17
0
7
1
View full text Add to dashboard Cite