Orientation of point nodes and nonunitary triplet pairing tuned by the easy-axis magnetization in UTe2
| Autor: | Yoshiya Homma, Dai Aoki, Yusei Shimizu, Dexin Li, Toshiro Sakakibara, Fuminori Honda, A. Nakamura, Shunichiro Kittaka, Kazushige Machida |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Superconductivity
Physics Strongly Correlated Electrons (cond-mat.str-el) Condensed matter physics Condensed Matter - Superconductivity FOS: Physical sciences Superconductivity (cond-mat.supr-con) Orientation (vector space) Condensed Matter - Strongly Correlated Electrons Magnetic anisotropy Magnetization Condensed Matter::Superconductivity Pairing Point (geometry) Single crystal |
| Zdroj: | Physical Review Research. 2 |
| ISSN: | 2643-1564 |
| DOI: | 10.1103/physrevresearch.2.032014 |
| Popis: | The gap structure of a novel uranium-based superconductor UTe$_2$, situated in the vicinity of ferromagnetic quantum criticality, has been investigated via specific-heat $C(T,H,\Omega)$ measurements in various field orientations. Its angular $\Omega(\phi,\theta)$ variation shows a characteristic shoulder anomaly with a local minimum in $H \parallel a$ at moderate fields rotated within the $ab$ and $ac$ planes. Based on the theoretical calculations, these features can be attributed to the presence of point nodes in the superconducting gap along the $a$ direction. Under the field orientation along the easy-magnetization $a$ axis, an unusual temperature dependence of the upper critical field at low fields together with a convex downward curvature in $C(H)$ were observed. These anomalous behaviors can be explained on the basis of a nonunitary triplet state model with equal-spin pairing whose $T_{\rm c}$ is tuned by the magnetization along the $a$ axis. From these results, the gap symmetry of UTe$_2$ is most likely described by a vector order parameter of $d(k)=(b + ic)(k_b + ik_c)$. Comment: 6 pages, 4 figures (main text) + 7 pages, 5 figures (Supplementary Material), accepted for publication in Phys. Rev. Research |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|