Crystal growth and magnetic properties of quantum spin liquid candidate KErTe₂

Recently rare-earth chalcogenides have been revealed as a family of quantum spin liquid (QSL) candidates hosting a large number of members. In this paper we report the crystal growth and magnetic measurements of KErTe₂, which is the first member of telluride in the family. Compared to its cousins of oxides, sulfides and selenides, KErTe₂ retains the high symmetry of R3m and Er³⁺ ions still sit on a perfect triangular lattice. The separation between adjacent magnetic layers is expectedly increased, which further enhances the two dimensionality of the spin system. Specific heat and magnetic susceptibility measurements on KErTe₂ single crystals reveal no structural and magnetic transition down to 1.8 K. Most interestingly, the absorption spectrum shows that the charge gap of KErTe₂ is roughly 0.93±0.35 eV, which is the smallest among all the reported members in the family. This immediately invokes the interest towards metallization even superconductivity using the compound.