High-pressure synthesis of yttrium-thorium sesquicarbide: A new high-temperature superconductor

Krupka, M.C.; Giorgi, A.L.; Krikorian, N. H.; Szklarz, E.G.

doi:10.1016/0022-5088(69)90026-5

Cited by 102 publications

(26 citation statements)

References 5 publications

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“…6 The rare earth sesquicarbides, R 2 C 3 (R = Rare earths), which crystallize in the bcc Pu 2 C 3 structuretype, have been suggested as possible candidates, in which such conditions are realized. Early on, T c of La 2 C 3 and Y 2 C 3 was found to be ∼ 11 K, and Th doping in Y 2 C 3 raises T c to 17 K, 7 comparable with the T c 's of the A15 compounds. In the Pu 2 C 3 structure, C 2 dumbbells are located inside the rare earth metal atom cage.…”

Section: Introductionmentioning

confidence: 85%

Strong electron-phonon coupling in the rare-earth carbide superconductorLa2C3

Kim

Xie²,

Kremer³

et al. 2007

Phys. Rev. B

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We present the results of a crystal structure determination using neutron powder diffraction as well as the superconducting properties of the rare-earth sesquicarbide La2C3 (Tc ≈ 13.4 K) by means of specific heat and upper critical field measurements. From the detailed analysis of the specific heat and a comparison with ab-initio electronic structure calculations, a quantitative estimate of the electron-phonon coupling strength and the logarithmic average phonon frequency is made. The electron-phonon coupling constant is determined to λ ph ∼ 1.35. The electron-phonon coupling to low energy phonon modes is found to be the leading mechanism for the superconductivity. Our results suggest that La2C3 is in the strong coupling regime, and the relevant phonon modes are Larelated rather than C-C stretching modes. The upper critical field shows a clear enhancement with respect to the Werthamer-Helfand-Hohenberg prediction, consistent with strong electron-phonon coupling. Possible effects on the superconducting properties due to the non-centrosymmetry of the crystal structure are discussed.

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Section: Introductionmentioning

confidence: 85%

Strong electron-phonon coupling in the rare-earth carbide superconductorLa2C3

Kim

Xie²,

Kremer³

et al. 2007

Phys. Rev. B

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“…Such materials predate the discovery of UcS in the non-centrosymmetric, highly correlated CePt3Si by over three decades, and include the high Tc (17 K) Y0.7Th0.3C1.5 (discovered by M.C. Krupka et al [583]), where the specific heat  is only (Stewart, Giorgi and Krupka [584]) 4.7 mJ/molK 2 . Theoretically, non-centrosymmetric superconductors have been calculated to show a rich variety of complex phenomena, including -e. g. in quasiparticle tunneling -multigap features and spin currents carried by surface states.…”

Section: Low Correlation Asoc Induced Examplesmentioning

confidence: 99%

Unconventional superconductivity

Stewart

2017

Advances in Physics

221

165

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Abstract:"Conventional" superconductivity, as used in this review, refers to electron-phonon coupled superconducting electron pairs described by BCS theory. Unconventional superconductivity refers to superconductors where the Cooper pairs are not bound together by phonon-exchange but instead by exchange of some other kind, e. g. spin fluctuations in a superconductor with magnetic order either coexistent or nearby in the phase diagram. Such unconventional superconductivity has been known experimentally since heavy fermion CeCu2Si2, with its strongly correlated 4f electrons, was discovered to superconduct below 0.6 K in 1979. Since the discovery of unconventional superconductivity in the layered cuprates in 1986, the study of these materials saw Tc jump to 164 K by 1994. Further progess in high temperature superconductivity would be aided by understanding the cause of such unconventional pairing. This review compares the fundamental properties of 9 unconventional superconducting classes of materialsfrom 4f-electron heavy fermions to organic superconductors to classes where only three known members exist to the cuprates with over 200 examples -with the hope that common features will emerge to help theory explain (and predict!) these phenomena. In addition, three new emerging classes of superconductors (topological, interfacial -e. g. FeSe on SrTiO3, and H2S under high pressure) are briefly covered, even though their "conventionality" is not yet fully determined.

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“…이 화합물에서는 강한 전자상호작용이 있을 것으로 생각되지 않음에도 불구하고 상대적으로 높은 온도에서 초전도 상전이가 관측되었다 [1][2][3][4][5]. 예를 들어 고온고압장비로 합성된 Y2C3의 경우는 Th도핑을 통해 초전도 상전이 온도 Tc가 17 K까지 올라가는 것이 관측되었다가 [1] 이후 Th 도핑 없이도 18 K의 초전도 상전이가 발견되었다 [2,3].…”

Section: 서 론 희토류 탄화물 R2c3 (R = 희토류)는 체심 입방구조를unclassified

Transport properties of carbide superconductor La₂C₃

Kim¹,

Kremer²

2013

Progress in Superconductivity and Cryogenics

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서 론 희토류 탄화물 R2C3 (R = 희토류)는 체심 입방구조를 AbstractWe investigate the electrical and thermal transport properties of a sesquicarbide superconductor La 2 C 3 , including electrical resistivity, thermoelectric power, and thermal conductivity. The electrical resistivity exhibits a typical metallic character with a saturation behavior at high temperatures. The thermoelectric power shows a metallic behavior with pronounced phonon-drag effect, comparable with pure metals. The broad peak of the thermal conductivity is observed in the superconducting state, which is rapidly suppressed by magnetic fields. These observations suggest that the electron-phonon scattering is significant in La 2 C 3 , which is relevant with the relatively high-T c in La 2 C 3 through strong electron-phonon coupling with low frequency phonon modes.

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High-pressure synthesis of yttrium-thorium sesquicarbide: A new high-temperature superconductor

Cited by 102 publications

References 5 publications

Strong electron-phonon coupling in the rare-earth carbide superconductorLa2C3

Strong electron-phonon coupling in the rare-earth carbide superconductorLa2C3

Unconventional superconductivity

Transport properties of carbide superconductor La₂C₃

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High-pressure synthesis of yttrium-thorium sesquicarbide: A new high-temperature superconductor

Cited by 102 publications

References 5 publications

Strong electron-phonon coupling in the rare-earth carbide superconductorLa2C3

Strong electron-phonon coupling in the rare-earth carbide superconductorLa2C3

Unconventional superconductivity

Transport properties of carbide superconductor La2C3

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Product

Resources

About

Transport properties of carbide superconductor La₂C₃