Anisotropic Multiband Many-Body Interactions in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>LuNi</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">B</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mi mathvariant="normal">C</mml:mi></mml:math>

Bergk, B.; Petzold, Vivien; Rösner, H.; Drechsler, S.‐L.; Bartkowiak, M.; Ignatchik, O.; Bianchi, A.; Sheikin, I.; Canfield, Paul C.; Wosnitza, J.

doi:10.1103/physrevlett.100.257004

Cited by 36 publications

(44 citation statements)

References 39 publications

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“…This calculation gives different BCS-extrapolation data for T c of the larger and smaller OPs, which points to the multiband nature of superconductivity in ErNi 2 B 2 C. Its physical sense is that there are FS parts with a weaker electron-phonon interaction (EPI) in which the temperature induced suppression of superconductivity is faster. This is supported by the calculation of the anisotropy of the EPI parameter in LuNi 2 B 2 C [4], which can vary from 0.3÷0.8 on a spheroidal FS to 1.0÷2.7 on a cube-like FS.…”

Section: Discussionmentioning

confidence: 69%

“…As in [19], the pair-breaking parameter γ increases in the vicinity of magnetic transitions, which is natural to attribute to the effect of spin fluctuations under a change of the magnetic order. 4. It has been shown that the proper choice of the scaling factor S in the one-gap GBTK calculation gives the ratio 2∆(0)/kT c ∼3.52 for the gap in the PM region and its BCS-like temperature dependence.…”

Section: Discussionmentioning

confidence: 99%

“…They have a rather complex Fermi surface (FS) consisting of several sheets [4,5]. FS is anisotropic [1,2] and has two characteristic groups of electrons possessing different Fermi velocities ν F (this was mentioned in [6] from the de Haasvan Alphen experiments [7,8].…”

Section: Introductionmentioning

confidence: 99%

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Observation of an anisotropic effect of antiferromagnetic ordering on the superconducting gap in ErNi2B2C

Bobrov

Chernobay

Naǐdyuk

et al. 2010

Low Temperature Physics

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The point-contact (PC) spectra of the Andreev reflection dV /dI curves of the superconducting rare-earth nickel borocarbide ErNi2B2C (Tc ≈11 K) have been analyzed in the "one-gap" and "two-gap" approximations using the generalized Blonder-Tinkham-Klapwijk (GBTK) model and the Beloborod'ko (BB) model allowing for the pair-breaking effect of magnetic impurities. Experimental and calculated curves have been compared not only in shape, but in magnitude as well, which provide more reliable data for determining the temperature dependence of the energy gap (or superconducting order parameter) ∆(T). The anisotropic effect of antiferromagnetic ordering at TN ≈6 K on the superconducting gap/order parameter has been determined: as the temperature is lowered, ∆ decreases by ∼25% in the c-direction and only by ∼4% in the ab-plane. It is found that the pair-breaking parameter increases in the vicinity of the magnetic transitions, the increase being more pronounced in the c-direction. The efficiency of the models was tested for providing ∆(T) data for ErNi2B2C from Andreev reflection spectra.

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Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Observation of an anisotropic effect of antiferromagnetic ordering on the superconducting gap in ErNi2B2C

Bobrov

Chernobay

Naǐdyuk

et al. 2010

Low Temperature Physics

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“…The unusual properties in the superconducting state led to controversial debates on its nature. In particular, these materials were among the first for which multiband superconductivity was detected [26][27][28][29]. Furthermore, pronounced gap anisotropies have been suggested [30,31].…”

Section: And References Therein)mentioning

confidence: 99%

Field-induced gapless electron pocket in the superconducting vortex phase ofYNi2B2Cas probed by magnetoacoustic quantum oscillations

et al. 2017

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By use of ultrasound studies we resolved magneto-acoustic quantum oscillation deep into the mixed state of the multiband nonmagnetic superconductor YNi2B2C. Below the upper critical field, only a very weak additional damping appears that can be well explained by the field inhomogeneity caused by the flux-line lattice in the mixed state. This is clear evidence for no or a vanishingly small gap for one of the bands, namely, the spheroidal α band. This contrasts de Haas-van Alphen data obtained by use of torque magnetometry for the same sample, with a rapidly vanishing oscillation signal in the mixed state. This points to a strongly distorted flux-line lattice in the latter case that, in general, can hamper a reliable extraction of gap parameters by use of such techniques. † This work is dedicated to the memory of Lev Petrovich Gor'kovThe observation of magnetic quantum oscillations is usually taken as evidence for the existence of a Fermi surface. The appearance of Landau levels in a magnetic field leads to an oscillating density of states at the Fermi level as a function of field. Experimentally, these oscillations can be detected in many thermodynamic and transport properties, with the most prominent being the de Haas-van Alphen (dHvA) effect in the magnetization. Consequently, the observation of dHvA oscillations in the mixed state of a superconductor first appeared as a surprise [1]. Below the upper critical field, B c2 , the opening of a superconducting gap and the corresponding disappearance of the entire Fermi surface seem to contradict the existence of such oscillations. Nevertheless, they were observed in many type-II superconductors ([2-4] and references therein).Motivated by the experimental evidence, however, it subsequently was shown by a number of theoretical studies that this phenomenon may be understood in principle in a rather general context. Thereby, different models are used to explain the occurrence of quantum oscillations below B c2 [5-9], but it still remains unclear which of them is the most appropriate. Usually, the validity of these theories is tested by comparing the predicted additional damping of the quantum oscillations below B c2 with experiment. Such analysis gives as the main fit parameter the superconducting gap at zero temperature, ∆ 0 , a value that largely depends on the used model.With the proper theory at hand dHvA data could, in principle, yield information on the field and angular evolution of the superconducting gap, ∆. However, considerable ambiguity in ∆ is introduced not only by the various theoretical predictions but even more from varying, sometimes contradictory, experimental data. In particular, for YNi 2 B 2 C and LuNi 2 B 2 C highly controversial results were reported [4,[10][11][12][13][14][15][16][17][18]. Thereby, for the so-called α band, an additional damping of the dHvA signal was found either in line with the opening of a weak-coupling gap [11][12][13]15], or yielding an unexpectedly small gap [4,10,14,17,18], or even an abrupt vanishing of the oscillatio...

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“…This compound crystallizes in CeScSi or UGeTe prototype structure belonging to the tetragonal I4/mmm space group with lattice parameters a = 3.754 Å and c = 14.488 Å. This prototype structure it is similar to the quaternary LuNi 2 B 2 C which is the prototype structure of many boron-carbide superconducting materials which offer interesting opportunities for the study of multiband behavior and the coexistence between superconductivity and magnetism [8][9][10][11][12][13][14]. Indeed, superconductivity in layer compounds often produces unusual results and at the same time offers a modern view for the occurrence of superconductivity [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%