Multigap nodeless superconductivity in the topological semimetal PdTe

作者：Chengcheng Zhao, Xiangqi Liu, Jinjin Wang, Chunqiang Xu, Baomin Wang, Wei Xia, Zhenhai Yu, Xiaobo Jin, Xu Zhang, Jing Wang, Dongzhe Dai, Chengpeng Tu, Jiaying Nie, Hanru Wang, Yihan Jiao, Daniel Duong, Silu Huang, Rongying Jin, Zhu‐An Xu, Yanfeng Guo, Xiaofeng Xu, Shiyan Li · 发表于：Physical review. B./Physical review. B · 年份：2024 · DOI：10.1103/physrevb.109.174502 · 被引用次数：9 · 研究领域：Topological Materials and Phenomena、Graphene research and applications、Advanced Condensed Matter Physics

Recently, PdTe was identified as a spin-orbit-coupled topological Dirac semimetal and was claimed to exhibit both bulk-nodal and surface-nodeless superconducting gaps. Here we report on ultra-low-temperature thermal-conductivity measurements on PdTe single crystals with ${T}_{c}$ = 4.5 K to investigate its superconducting gap structure. It is found that the residual linear term ${\ensuremath{\kappa}}_{0}/T$ is negligible in zero magnetic field. Furthermore, the field dependence of ${\ensuremath{\kappa}}_{0}(H)/T$ exhibits an $\mathsf{S}$-shaped curve. These results suggest that PdTe has multiple nodeless superconducting gaps, which is at odds with the claimed bulk-nodal gap. The reason for the discrepancy is likely that previous angle-resolved photoemission spectroscopy measurements were only performed down to 2 K and cannot observe the smaller nodeless gap. The fully gapped superconducting state in PdTe is compatible with it being a topological superconductor candidate.