Phase diagram of the unconventional superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">UPt</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>in the weak-crystal-field model

Zhitomirsky, M. E.; Ueda, Kazuo

doi:10.1103/physrevb.53.6591

Cited by 19 publications

(25 citation statements)

References 53 publications

(91 reference statements)

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“…The singlet pairing based on the IRs A 1g and E 1g was also considered in [28]. The model of [29] includes the A 1 E 1 symmetry of the superconducting state. Thus almost all the IRs of the D 6h point group have been discussed as possible candidates for the desription of the superconducting state in UPt 3 .…”

Section: Comparison With Experiments and Discussionmentioning

confidence: 99%

Space-Group Approach to the Nodal Structure of the Superconducting Order Parameter in UPt3

Yarzhemsky

1998

phys. stat. sol. (b)

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The nodal structure of the superconducting order parameter (SOP) in D 4 6h symmetry (crystal symmetry of UPt 3 ) is investigated making use of the space-group approach to the wave function of a Copper pair. It is shown that the lines of nodes of odd SOP appear in strong spin±orbit coupling case if the time-reversal symmetry is violated. The nodal structure of the SOP is defined by the space±time symmetry of the crystal and does not depend on any choice of basis functions. The theoretical nodal structure of the E 1u in D 4 6h symmetry agrees with the experimental data on UPt 3 .

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Section: Comparison With Experiments and Discussionmentioning

confidence: 99%

Space-Group Approach to the Nodal Structure of the Superconducting Order Parameter in UPt3

Yarzhemsky

1998

phys. stat. sol. (b)

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“…In spite of these prominent features, the superconducting gap structure still remains to be solved. Many scenarios have been proposed based on the phenomenological approach so far [13][14][15][16]. Among them, the most promising gap symmetry has been widely believed to be E 2u models [1,[17][18][19].…”

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confidence: 99%

Exotic Multigap Structure in UPt3 Unveiled by a First-Principles Analysis

Nomoto

Ikeda

2016

Phys. Rev. Lett.

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A heavy-fermion superconductor UPt3 is a unique spin-triplet superconductor with multiple superconducting phases. Here we provide the first report on the first-principles analysis of the microscopic superconducting gap structure. We find that the promising gap structure is an unprecedented E2u state, which is completely different from the previous phenomenological E2u models. Our obtained E2u state has in-plane twofold vertical line nodes on small Fermi surfaces and point nodes with linear dispersion on a large Fermi surface. These peculiar features cannot be explained in the conventional spin 1/2 representation, but is described by the group-theoretical representation of the Cooper pairs in the total angular momentum j = 5/2 space. Our findings shed new light on the long-standing problems in the superconductivity of UPt3.PACS numbers: 74.20.Mn, 74.20.Pq, 74.20.Rp,74.70.Tx Identifying the pairing state and the pairing mechanism is one of the most interesting and important issues in the field of unconventional superconductivity. In particular, a spin-triplet type of pairing state attracts much attention, since there are few examples except for the superfluid helium 3. In the strongly correlated electron systems, the heavy-fermion superconductor UPt 3 is one of the rare candidates for spin-triplet superconductors [1,2]. The most impressive feature of this material is the multiple superconducting phase diagram. At zero magnetic field, there appears the superconducting double transition into the A phase at the upper critical temperature T + c ∼ 540mK, and then into the B phase at the lower T − c ∼ 490mK [3]. Moreover, the C phase appears at high field and low temperature in the H − T phase diagram [4,5]. In each phase, nodal quasiparticle excitations have been observed [6][7][8][9], and also the time-reversal symmetry breaking has been reported in B phase [10][11][12]. In spite of these prominent features, the superconducting gap structure still remains to be solved. Many scenarios have been proposed based on the phenomenological approach so far [13][14][15][16]. Among them, the most promising gap symmetry has been widely believed to be E 2u models [1,[17][18][19]. However, recent measurement of the fieldangle resolved thermal transport has detected in-plane twofold oscillations in the C phase [20]. This result is inconsistent with the proposed E 2u models, because in the group-theoretical argument, it is believed that the E 2u models do not have such in-plane twofold symmetry. Such twofold symmetry seems to be rather compatible with the E 1u models proposed in Refs. [21][22][23]. This is also supported by the following observations. A small residual thermal conductivity [24] suggests the presence of point nodes with linear dispersion in the E 1u models. The Josephson effect [25] with s-wave superconductor is compatible with E 1u planar states. Thus, recently, the * nomoto.takuya@scphys.kyoto-u.ac.jp E 1u models [21][22][23] have been revisited. This strongly promoted the field-angle resolved specific heat measur...

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“…Theoretically, several papers propose two-dimensional even parity states, i.e. singlet pairing states, 3,4,5) while others suggest triplet pairing states belonging to the onedimensional representation (A u ) 6,7) and to the two-dimensional representation (E u ). 8,9) Although theoretical 10,11,12) and experimental 13,14,15,16,17) spectroscopic studies of the thermal conduction and transverse sound attenuation of UPt 3 have been performed, the symmetry of the pair potential…”

Section: §1 Introductionmentioning

confidence: 99%

Theory of Tunneling Conductance for Normal Metal/Insulator/ Triplet Superconductor Junction

et al. 1998

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Tunneling conductance spectra of normal metal/insulator/triplet superconductor junctions are investigated theoretically. As triplet paring states we select several types of symmetries that are promising candidates for the superconducting states in UPt 3 and in Sr 2 RuO 4 . The calculated conductance spectra are sensitive to the orientation of the junction which reflects the anisotropy of the pairing states. They show either zero-bias conductance peaks or gap-like structures depending on the orientation of the junctions. The existence of a residual density of states, peculiar to nonunitary states, is shown to have a significant influence on the properties of the conductance spectra. Present results serve as a guide for the experimental determination of the symmetry of the pair potentials in UPt 3 and Sr 2 RuO 4 .KEYWORDS: triplet superconductor, nonunitary pair potential, zero-bias conductance peak, §1. IntroductionSince the discovery of superconductivity in heavy fermion compounds the determination of the symmetry of the pair potential in these materials has been an important issue. 1) Among the heavy fermion superconductors, so far properties of UPt 3 have been studied most extensively. Based on NMR experiments 2) the possibility of odd parity pairing states, i.e., triplet pairing states, has been suggested. Theoretically, several papers propose two-dimensional even parity states, i.e. singlet pairing states, 3,4,5) while others suggest triplet pairing states belonging to the onedimensional representation (A u ) 6, 7) and to the two-dimensional representation (E u ). 8, 9) Although theoretical 10,11,12) and experimental 13,14,15,16,17) spectroscopic studies of the thermal conduction and transverse sound attenuation of UPt 3 have been performed, the symmetry of the pair potentialcould not yet been determined.Recently superconductivity has been discovered in Sr 2 RuO 4 , 18) which is the first example of a noncuprate layered perovskite superconductor. Since this compound is isostructual to the cuprate superconductors the electronic properties in the normal state 19) Phase-sensitive measurements provide the most useful information for the determination of the symmetry of the pair potentials. 27) Recently it was shown that tunneling spectroscopy has the ability to detect the phase of the pair potential, 28,29,30) as follows: In anisotropic superconductors quasiparticles feel different signs of the pair potentials depending on the directions of their motions. 31) At the normal metal/superconductor interface the anisotropy of the pair potential significantly influences the properties of the Andreev reflections. 32, 33) As a result tunneling conductance spectra of the normal metal/insulator/anisotropic superconductor junctions are modified due to the anisotropy of pair potential. 28,29) The most remarkable feature is the existence of zerobias conductance peaks (ZBCP) in the tunneling spectra for d-wave symmetry. The origin of these peaks is the localized zero energy states (ZES) 34) due to the change of sign of the p...

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Phase diagram of the unconventional superconductorUPt3in the weak-crystal-field model

Cited by 19 publications

References 53 publications

Space-Group Approach to the Nodal Structure of the Superconducting Order Parameter in UPt3

Space-Group Approach to the Nodal Structure of the Superconducting Order Parameter in UPt3

Exotic Multigap Structure in UPt3 Unveiled by a First-Principles Analysis

Theory of Tunneling Conductance for Normal Metal/Insulator/ Triplet Superconductor Junction

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