D-wave superconductivity in heavy fermion systems

Yin, Guimei; Maki, Kazumi

doi:10.1016/0921-4526(94)91792-2

Cited by 6 publications

(6 citation statements)

References 14 publications

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“…6 we show the measured dκ/dT at T c as a function of the magnetic field, normalized to the normal state values : (dκ s /dT −dκ n /dT )/(κ n /T c (B)), where the subscript s means approaching T c from the superconducting state, and n from the normal state. As already mentioned [25,26] and shown by the measurements of Behnia et al [3,4] in UPt 3 , the slope dκ s /dB, and therefore also dκ s /dT, depends on the direction of current and field, and is related to the gap structure. Therefore, if the topology of the gap changes when passing from the high temperature low field A phase to the low temperature high field C phase, a jump of dκ/dT should be observed at the A→C phase transition.…”

Section: Mixed Phasementioning

confidence: 63%

“…In the literature (see Refs. [3,4,25,26] for the discussion of UPt 3 ), it is generally the jump in dκ/dB which is discussed. We have measured dκ/dT because our resolution for temperature scans was much better than for field scans, but the main conclusions should remain the same.…”

Section: Superconducting Phasementioning

confidence: 99%

“…We discuss extensively our zero field data, and also present new measurements under magnetic fields. Measurements under field in the mixed state give an additional means of probing the gap structure [3,4,[24][25][26]. Indeed, the possibility of a hybrid gap such as that in the E 1g and E 2u models was proposed by Yin and Maki [25] on the basis of the mixed state thermal conductivity data of Behnia et al [3,4].…”

Section: Introductionmentioning

confidence: 99%

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Thermal conductivity and gap structure of the superconducting phases of UPt3

et al. 1997

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Section: Mixed Phasementioning

confidence: 63%

Section: Superconducting Phasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal conductivity and gap structure of the superconducting phases of UPt3

et al. 1997

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“…This can have a significant effect on transport quantities, as pointed out by Yin and Maki. [23] Fledderjohann and Hirschfeld [8] exploited this to show that the thermal conductivity anisotropy ratio, κ c (0)/κ b (0), is small for the E 1g case (it would be zero in the clean limit), but is unity for the E 2u case, at least for an ellipsoidal Fermi surface, with the data of Lussier et al [7] lying between these two results but being more consistent with E 1g than E 2u . This in turn motivated Lussier et al to take data at lower temperatures, where they conclude that the extrapolated T=0 anisotropy ratio of about 0.5 is probably intrinsic and thus consistent with an E 2u model.…”

Section: Order Parameters and Fermi Surfacesmentioning

confidence: 80%

Heat transport and the nature of the order parameter in superconductingUPt3

Norman

Hirschfeld

1996

Phys. Rev. B

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Recent thermal conductivity data on the heavy fermion superconductor U P t3 have been interpreted as offering support for an E2u model of the order parameter as opposed to an E1g model. In this paper, we analyze this issue from a theoretical standpoint including the detailed effects of Fermi surface and gap anisotropy. Our conclusion is that although current data put strong constraints on the gap anisotropy, they cannot definitively distinguish between these two models. Measurements on samples of varying quality could be decisive in this regard, however.

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“…Some of these have interesting features, but often too little is known about the theory to give a reasonable evaluation. Three examples are as follows: superconductivity is connected to a rotation of the magnetic moment (Blount, Varma, and Aeppli, 1990); the order parameter is nonunitary and belongs to the E 1u representation Machida, 1996a, 1996b), or the order parameter belongs to the E 2g representation (Yin and Maki, 1994). There is also an interesting theory based on combining the oddfrequency pairing hypothesis with a novel picture of the normal-state quasiparticles to produce a magnetic superconducting ordering (Coleman, Miranda, and Tsvelik, 1994).…”

Section: Other Theoriesmentioning

confidence: 99%

The superconducting phases ofUPt3

2002

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The heavy-fermion compound UPt 3 is the first compelling example of a superconductor with an order parameter of unconventional symmetry. To this day, it is the only unambiguous case of multiple superconducting phases. Twenty years of experiment and theory on the superconductivity of UPt 3 are reviewed, with the aim of accounting for the multicomponent phase diagram and identifying the superconducting phases. First, the state above the superconducting critical temperature at T c ϭ0.5 K is briefly described: de Haas-van Alphen and other measurements demonstrate that this state is a Fermi liquid, with degeneracy fully achieved at T c . This implies that the usual BCS theory of superconductivity should hold, although the strong magnetic interactions suggest the possibility of an unconventional superconducting order parameter. The role of the weak antiferromagnetic order below T N ϭ5 K in causing phase multiplicity is examined. A comprehensive analysis of which superconducting states are possible is given, and the theoretical basis for each of the main candidates is considered. The behavior of various properties at low temperature (TӶT c ) is reviewed. The experiments clearly indicate the presence of nodes in the superconducting gap function of all three phases. In particular, the low-temperature low-field phase has a gap with a line node in the basal plane and point nodes along the hexagonal c axis. The phase diagram in the magnetic-field-temperature plane has been determined in detail by ultrasound and thermodynamic measurements. Experiments under pressure indicate a coupling between antiferromagnetism and superconductivity and provide additional clues about the order parameter. Theoretically, Ginzburg-Landau theory is the tool that elucidates the phase diagram, while calculations of the temperature and field dependence of physical quantities have been used to compare different order parameters to experiment. On balance, the data point to a two-component order parameter belonging to either the E 1g or the E 2u representation, with degeneracy lifted by a coupling to the symmetry-breaking magnetic order. However, no single theoretical scenario is completely consistent with all the data. The coupling of superconductivity and magnetism may be the weakest link in the current picture of UPt 3 , and full understanding depends on the resolution of this issue.

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D-wave superconductivity in heavy fermion systems

Cited by 6 publications

References 14 publications

Thermal conductivity and gap structure of the superconducting phases of UPt3

Thermal conductivity and gap structure of the superconducting phases of UPt3

Heat transport and the nature of the order parameter in superconductingUPt3

The superconducting phases ofUPt3

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