Complicated magnetic phases interplayed with charge density waves in a new topological semimetal

Topological semimetals have attracted a lot of attentions as they provide a new platform for studies of quantum matter as well as offer a new paradigm for next-generation electronics. Within these discovered topological materials, there is a class of materials that share the same structural motifs—sheets of square-arranged atoms, such as that in ZrSiS, CeSbTe and SrMnBi2. Within these materials, CeSbTe stands out as one unique system that offers the opportunities to study its tunable Weyl and Dirac states due to the existence of field-induced magnetic phase transitions. Here in this work, we present the synthesis and characterizations of a new series of square-net-based magnetic topological semimetals. Based on a comprehensive structural characterization by powder x-ray diffraction, single crystal x-ray analysis, and transmission electron microscopy on this series of compounds, we observed a crystal symmetry evolution from an orthorhombic phase to a tetragonal one, in accompany with a tunable charge density wave (CDW) modulation. Besides the structural characterizations, we have also performed a comprehensive study on the magnetic properties. The impact of crystal symmetry evolution and CDW on the linear crossing band is also discussed.