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arXiv · 1709.00128

Quasiparticle Excitations and Evidence for Superconducting Double Transitions in Monocrystalline U0.97Th0.03Be13

Yusei Shimizu·Shunichiro Kittaka·Shota Nakamura·Toshiro Sakakibara·Dai Aoki·Yoshiya Homma·Ai Nakamura·Kazushige Machida
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Abstract

Superconducting (SC) gap symmetry and magnetic response of cubic U0.97Th0.03Be13 are studied by means of high-precision heat-capacity and dc magnetization measurements using a single crystal, in order to address the long-standing question of its second phase transition at Tc2 in the SC state below Tc1. The absence (presence) of an anomaly at Tc2 in the field-cooling (zero-field-cooling) magnetization indicates that this transition is between two different SC states. There is a qualitative difference in the field variation of the transition temperatures; Tc2(H) is isotropic whereas Tc1(H) exhibits a weak anisotropy between [001] and [111] directions. In the low temperature phase below Tc2(H), the angle-resolved heat-capacity $C(T,H, ϕ)$ reveals that the gap is fully opened over the Fermi surface, narrowing down the possible gap symmetry.

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Yusei Shimizu, Shunichiro Kittaka, Shota Nakamura, Toshiro Sakakibara, Dai Aoki, Yoshiya Homma, Ai Nakamura, Kazushige Machida. 2017-09-01. Quasiparticle Excitations and Evidence for Superconducting Double Transitions in Monocrystalline U0.97Th0.03Be13. https://doi.org/10.1103/physrevb.96.100505

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