Observation of Dirac nodal line states in topological semimetal candidate PrSbTe
Dengpeng Yuan, Dajian Huang, Xin Ma, Chen Xu, Huifen Ren, Yun Zhang, Wei Feng, Xiegang Zhu, Bo Wang, Xuwen He, Jian Wu, Shiyong Tan, Qunqing Hao, Qiang Zhang, Yi Liu, Qin Liu, Zhengtai Liu, Chao Cao, Qiuyun Chen, Xinchun Lai
Abstract
The interplay among topology, crystal symmetry, magnetic order, and strong electron correlation can give rise to a plethora of exotic physical phenomena. The ZrSiS family is known as typical topological Dirac semimetals, among them $\mathit{Ln}\mathrm{SbTe}$ ($\mathit{Ln}$ denotes lanthanide) compounds exhibit intriguing characteristics due to the presence of $\mathit{Ln} 4f$ electrons, resulting in quantum states and unique properties. In this paper, the topological electronic structure of PrSbTe is systematically studied by angle-resolved photoemission spectroscopy (ARPES), combined with magnetic, specific heat measurements, and band structure calculations. The detailed three-dimensional electronic structure of PrSbTe has been obtained, and a diamond-shaped Fermi surface and multiple Dirac nodal lines have been observed, which are in remarkable agreement with theoretical calculations. Moreover, the $4f$ electrons in PrSbTe are rather localized, which can be revealed by on-resonant ARPES data and further confirmed by the rather small Sommerfeld coefficient of $\ensuremath{\gamma}=2.6231\phantom{\rule{0.16em}{0ex}}\mathrm{mJ}/\mathrm{mol}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{2}$. Our results provide more detailed information about the $\mathit{Ln}\mathrm{SbTe}$ family, which gives a deeper understanding of the interaction between $\mathit{Ln} 4f$ electrons and the topological states.