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 the ultralow-temperature thermal conductivity measurements on PdTe single crystals with Tc = 4.5 K to investigate its superconducting gap structure. It is found that the residual linear term κ0/T is negligible in zero magnetic field. Furthermore, the field dependence of κ0(H)/T exhibits an 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.
@article{arxiv.2310.08462,
title = {Multigap nodeless superconductivity in the topological semimetal PdTe},
author = {Chengcheng Zhao and Xiangqi Liu and Jinjin Wang and Chunqiang Xu and Baomin Wang and Wei Xia and Zhenhai Yu and Xiaobo Jin and Xu Zhang and Jing Wang and Dongzhe Dai and Chengpeng Tu and Jiaying Nie and Hanru Wang and Yihan Jiao and Daniel Duong and Silu Huang and Rongying Jin and Zhu'an Xu and Yanfeng Guo and Xiaofeng Xu and Shiyan Li},
journal= {arXiv preprint arXiv:2310.08462},
year = {2023}
}