Single-gap two-band superconductivity well above the Pauli limit in non-centrosymmetric TaIr$_2$B$_2$

J. Kacmarcik; Z. Pribulova; T. Shiroka; F. Kosuth; P. Szabo; M. J. Winiarski; S. Krolak; J. Jaroszynski; T. Shang; R. J. Cava; C. Marcenat; T. Klein; T. Klimczuk; P. Samuely

doi:10.1016/j.supcon.2025.100167

arXiv · 2504.00662

Single-gap two-band superconductivity well above the Pauli limit in non-centrosymmetric TaIr$_2$B$_2$

J. Kacmarcik·Z. Pribulova·T. Shiroka·F. Kosuth·P. Szabo·M. J. Winiarski·S. Krolak·J. Jaroszynski·T. Shang·R. J. Cava·C. Marcenat·T. Klein·T. Klimczuk·P. Samuely

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Abstract

Non-centrosymmetric superconducting materials represent an exciting class of novel superconductors featuring a variety of unconventional properties, including mixed-parity pairing and very high upper critical fields. Here, we present a comprehensive study of TaIr$_2$B$_2$ (with $T_c$ = 5.1 K), using a set of complementary experimental methods, including bulk- and surface-sensitive techniques. We provide evidence that this system is a two-band, yet it behaves as a single-gap superconductor with a strong coupling. The upper critical field of TaIr$_2$B$_2$ significantly exceeds the Pauli limit and exhibits a nearly linear temperature dependence down to the lowest temperatures. This behavior, rarely seen in superconductors, is discussed in terms of anti-symmetric spin-orbit interaction, two-band-, and strong-coupling effects, as well as disorder.

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J. Kacmarcik, Z. Pribulova, T. Shiroka, F. Kosuth, P. Szabo, M. J. Winiarski, S. Krolak, J. Jaroszynski, T. Shang, R. J. Cava, C. Marcenat, T. Klein, T. Klimczuk, P. Samuely. 2025-04-01. Single-gap two-band superconductivity well above the Pauli limit in non-centrosymmetric TaIr$_2$B$_2$. https://doi.org/10.1016/j.supcon.2025.100167

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