Discovery of the type-II superconductor Ta4Rh2C1-δ with a high upper critical field

Keyuan Ma; Sara López-Paz; Karolina Gornicka; Harald O. Jeschke; Tomasz Klimczuk; Fabian O. Von Rohr

doi:10.1103/PhysRevResearch.7.023147

Discovery of the type-II superconductor Ta4Rh2C1-δ with a high upper critical field

Keyuan Ma
, Sara López-Paz
, Karolina Gornicka
, Harald O. Jeschke
, Tomasz Klimczuk
, Fabian O. Von Rohr

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Abstract

We report on the discovery of superconductivity in the previously unknown compound Ta4Rh2C1-δ. Ta4Rh2C1-δ crystallizes in the η-carbide structure type, in the cubic space group Fd3¯m (No. 227) with a unit cell parameter of a=11.7947 Å. Temperature-dependent magnetic susceptibility, resistivity, and specific-heat capacity measurements reveal that Ta4Rh2C1-δ is a type-II bulk superconductor with a critical temperature of Tc=6.4K and a normalized specific-heat jump ΔC/γTc=1.56. Notably, we find that Ta4Rh2C1-δ has a high upper critical field of μ0Hc2(0)=17.4T, which exceeds the BCS weak-coupling Pauli limit of μ0HPauli=11.9T.

Original language	English
Article number	023147
Journal	Physical Review Research
Volume	7
Issue number	2
DOIs	https://doi.org/10.1103/PhysRevResearch.7.023147
State	Published - Apr 2025
Externally published	Yes

Funding

This work was supported by the Swiss National Science Foundation under Grant No. PCEFP2_194183. Research performed at Gdansk University of Technology was supported by the National Science Center (Poland), Project No. 2022/45/B/ST5/03916.

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10.1103/PhysRevResearch.7.023147

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title = "Discovery of the type-II superconductor Ta4Rh2C1-δ with a high upper critical field",

abstract = "We report on the discovery of superconductivity in the previously unknown compound Ta4Rh2C1-δ. Ta4Rh2C1-δ crystallizes in the η-carbide structure type, in the cubic space group Fd3¯m (No. 227) with a unit cell parameter of a=11.7947 {\AA}. Temperature-dependent magnetic susceptibility, resistivity, and specific-heat capacity measurements reveal that Ta4Rh2C1-δ is a type-II bulk superconductor with a critical temperature of Tc=6.4K and a normalized specific-heat jump ΔC/γTc=1.56. Notably, we find that Ta4Rh2C1-δ has a high upper critical field of μ0Hc2(0)=17.4T, which exceeds the BCS weak-coupling Pauli limit of μ0HPauli=11.9T.",

author = "Keyuan Ma and Sara L{\'o}pez-Paz and Karolina Gornicka and Jeschke, \{Harald O.\} and Tomasz Klimczuk and \{Von Rohr\}, \{Fabian O.\}",

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AU - Ma, Keyuan

AU - López-Paz, Sara

AU - Gornicka, Karolina

AU - Jeschke, Harald O.

AU - Klimczuk, Tomasz

AU - Von Rohr, Fabian O.

N1 - Publisher Copyright: © 2025 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

PY - 2025/4

Y1 - 2025/4

N2 - We report on the discovery of superconductivity in the previously unknown compound Ta4Rh2C1-δ. Ta4Rh2C1-δ crystallizes in the η-carbide structure type, in the cubic space group Fd3¯m (No. 227) with a unit cell parameter of a=11.7947 Å. Temperature-dependent magnetic susceptibility, resistivity, and specific-heat capacity measurements reveal that Ta4Rh2C1-δ is a type-II bulk superconductor with a critical temperature of Tc=6.4K and a normalized specific-heat jump ΔC/γTc=1.56. Notably, we find that Ta4Rh2C1-δ has a high upper critical field of μ0Hc2(0)=17.4T, which exceeds the BCS weak-coupling Pauli limit of μ0HPauli=11.9T.

AB - We report on the discovery of superconductivity in the previously unknown compound Ta4Rh2C1-δ. Ta4Rh2C1-δ crystallizes in the η-carbide structure type, in the cubic space group Fd3¯m (No. 227) with a unit cell parameter of a=11.7947 Å. Temperature-dependent magnetic susceptibility, resistivity, and specific-heat capacity measurements reveal that Ta4Rh2C1-δ is a type-II bulk superconductor with a critical temperature of Tc=6.4K and a normalized specific-heat jump ΔC/γTc=1.56. Notably, we find that Ta4Rh2C1-δ has a high upper critical field of μ0Hc2(0)=17.4T, which exceeds the BCS weak-coupling Pauli limit of μ0HPauli=11.9T.

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Discovery of the type-II superconductor Ta4Rh2C1-δ with a high upper critical field

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