Two-Channel Kondo Effect in Glasslike ThAsSe

Cichorek, T.; Sanchez, Alvaro; Gegenwart, P.; Weickert, Franziska; Wojakowski, A.; Henkie, Z.; Auffermann, Gudrun; Paschen, S.; Kniep, Rüdiger; Steglich, F.

doi:10.1103/physrevlett.94.236603

Cited by 51 publications

(66 citation statements)

References 35 publications

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“…Here, the low-temperature r(T) data are shown as Dr/r (0.12 K) vs T 1/2 . Note that a very similar, magnetic-field-independent ÀAT 1/2 term has also been found in the isostructural phase ThAsSe [6].…”

Section: Physical Propertiesmentioning

confidence: 74%

“…This structural disorder is held responsible for the formation of two-level systems that are the cause of glass-type temperature dependencies of both the thermal conductivity and the specific heat in the millikelvin temperature range [6]. Most interestingly, the electrical resistivities of UAsSe, ThAsSe and ZrAs 1.40 show a low-temperature upturn, whose magnitude is unaffected by the application of a magnetic field.…”

Section: Introductionmentioning

confidence: 98%

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Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

Schlechte

Niewa

Schmidt

et al. 2007

Science and Technology of Advanced Materials

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Ternary phases in the systems Zr-As-Se and Zr-As-Te were studied using single crystals of ZrAs 1.40(1) Se 0.50(1) and ZrAs 1.60(2) Te 0.40(1) (PbFCl-type of structure, space group P4/nmm) as well as ZrAs 0.70(1) Se 1.30(1) and ZrAs 0.75(1) Te 1.25(1) (NbPS-type of structure, space group Immm). The characterization covers chemical compositions, crystal structures, homogeneity ranges and electrical resistivities. At 1223 K, the Te-containing phases can be described with the general formula ZrAs x Te 2Àx , with 1.53(1)pxp1.65(1) (As-rich) and 0.58(1)pxp0.75(1) (Te-rich). Both phases are located directly on the tie-line between ZrAs 2 and ZrTe 2 , with no indication for any deviation. Similar is true for the Se-rich phase ZrAs x Se 2Àx with 0.70(1)pxp0.75(1). However, the compositional range of the respective As-rich phase ZrAs xÀy Se 2Àx (0.03(1)pyp0.10(1); 1.42(1)pxp1.70(1)) is not located on the tie-line ZrAs 2 -ZrSe 2 , and exhibits a triangular region of existence with intrinsic deviation of the composition towards lower non-metal contents. Except for ZrAs 0.75 Se 1.25 , from the homogeneity range of the Se-rich phase, all compounds under investigation show metallic characteristics of electrical resistivity at temperatures 420 K. Related uranium and thorium arsenide selenides display a typical magnetic field-independent rise of the resistivity towards lower temperatures, which has been explained by a non-magnetic Kondo effect. However, a similar observation has been made for ZrAs 1.40 Se 0.50 , which, among the Zr-based arsenide chalcogenides, is the only system with a large concentration of intrinsic defects in the anionic substructure. r

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Section: Physical Propertiesmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 98%

Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

Schlechte

Niewa

Schmidt

et al. 2007

Science and Technology of Advanced Materials

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“…As can be seen from this figure, both of these temperature dependencies exhibit a minimum at about 25 K and form an upturn below that temperature. The occurrence of the lowtemperature minimum in ρ(T) may point to the presence of the two-channel Kondo effect derived from structural two-level energy systems [37], as discussed in detail for ThAsSe [38], for example. The obtained residual resistivity ratio (RRR) is rather small (about 4.5), but it is usually difficult for any thorium compound to obtain a high-quality single crystal.…”

Section: Transport Propertiesmentioning

confidence: 99%

Comparative studies of the cage systems ThFe2Al10 and UFe2Al10

Troć

Wawryk

Gajek

et al. 2017

Journal of Alloys and Compounds

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We have grown single crystals of ThFe 2 Al 10 and used them for the refinement of its crystal structure. From the specific heat data, we determined the phonon components, that is, the Debye and Einstein modes, for Th-and Ubased isostructural aluminides. To approximate the Sommerfeld coefficients, we had to include the T 3 lnT term characteristic of spin-fluctuations originating from the Fe-sublattice. The roughly estimated spin-fluctuation temperature is about 11 K. ThFe 2 Al 10 is a weakly temperature-dependent Pauli-paramagnet. However, at lower temperatures the ferromagnetic correlations are observed, which signals that the system drives to quantum criticality. The distinct minimum in electrical resistivity observed at about 20 K suggests a realization of a nonmagnetic two-channel Kondo-effect in ThFe 2 Al 10 , as discussed for ThAsSe [Phys. Rev. Lett. 94, 236603 (2005)], for example. The [ρ(T) -ρ min ] versus T curves of ThFe 2 Al 10 , determined along the a-and c-axes, were used to subtract the phonon contributions from the corresponding ρ(T) a,c of UFe 2 Al 10 . The resulting magnetic part of the average ρ m (T) av curve was then analysed in terms of the influence of the crystal field effect on the transport properties. However, to obtain agreement with the experiment, we had to take into account another effect, namely the Kondo-like one. This kind of probe has been applied for the first time in the case of uranium compounds. Based on the magnetoresistivity, we have revealed the anisotropic low-frequency vibrations of the Th atom (located in its [Al 16 Fe 4 ] cage) interacting with the conduction band, the phenomenon revealed previously in the metallic UB 12 [Phil. Mag. B 95, 2343]. Furthermore, fully relativistic band structure calculations performed for ThFe 2 Al 10 revealed its metallic-like character with a similarly large contribution of the Fe 3d electrons at the Fermi level as predicted previously for its 5f-electron analogue UFe 2 Al 10 . In addition, there are substantial differences between their Fermi surfaces.

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“…Obviously, this is not the case for HfAs 1.7 Se 0.2 , and hence EEI should be ruled out as a source of the magnetic-field-independent ÀAT 1/2 term in the resistivity. Finally, we note that, while a ÀAT 1/2 behavior was also observed in the related systems Th-As-Se [7] and Zr-As-Se, [5] their B 1/2 magnetoresistivity is negative in high magnetic fields. Thus, in the context of the common feature of 1(T) at B = const., that is, a magnetic-field-independent ÀAT 1/2 term, the different sign of the magnetoresistivity of various arsenide selenides of PbFCl structure type is surprising, and again is in contrast to the prediction for electron-electron interactions in a three-dimensional disordered metal.…”

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confidence: 82%

Crystal Chemistry and Physical Properties of the Nonmagnetic Kondo Compound HfAs_1.7Se_0.2

et al. 2010

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Single crystals of HfAs(1.7)Se(0.2) are grown by chemical transport reaction and their chemical composition characterized in detail by various analytical methods. Chemical analyses and crystal structure investigations by single-crystal X-ray diffraction as well as powder diffraction with synchrotron radiation reveal a tetragonal PbFCl structure type with strong disorder caused by a significant arsenic deficiency (As(0.9)) on the 2a site and mixed occupancy of the 2c site (As(0.8)Se(0.2)). HfAs(1.7)Se(0.2) is a diamagnetic metal which transforms into a superconducting state at T(c)=0.52 K. Similar to other PbFCl-type arsenide selenides, the title compound displays a magnetic-field-independent -AT(1/2) term in the low-temperature electrical resistivity. This unusual term presumably originates from the electron scattering of structural two-level systems. According to the experimental results, HfAs1.7Se0.2 appears to be a rare example of a nonmagnetic Kondo material.

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Two-Channel Kondo Effect in Glasslike ThAsSe

Cited by 51 publications

References 35 publications

Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

Comparative studies of the cage systems ThFe2Al10 and UFe2Al10

Crystal Chemistry and Physical Properties of the Nonmagnetic Kondo Compound HfAs_1.7Se_0.2

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Two-Channel Kondo Effect in Glasslike ThAsSe

Cited by 51 publications

References 35 publications

Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

Comparative studies of the cage systems ThFe2Al10 and UFe2Al10

Crystal Chemistry and Physical Properties of the Nonmagnetic Kondo Compound HfAs1.7Se0.2

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Crystal Chemistry and Physical Properties of the Nonmagnetic Kondo Compound HfAs_1.7Se_0.2