Evolution of Structure and Magnetism in the Square Net Series TbTe_2-xSb_x

Square net materials have attracted attention as platforms for studying the interplay between electronic topology, charge density order, superconductivity, and magnetism. A recent example was seen in GdSb_xTe_2-x-δ, where Sb substitution results in structural modulations that coincide with modification of the electronic state and magnetic order [1]. Motivated by this, we investigated TbTe_2-xSb_x (0 < x < 0.55)_, which is structurally similar - but additionally has an anisotropic f-state with a non-zero orbital quantum number. For the parent compound, we show that the crystal structure is consistent with the UAs₂ prototype, but there is evidence for superstructure formation that evolves as a function of x. TbTe₂ also exhibits an antiferromagnetically ordered state that is modified with increasing x. Trends in the series will be examined using bulk thermodynamic measurements, where we provide evidence for a complex evolution of structure and ground state ordered behaviors.

[1] Lei S., et al. Advanced Quantum Technologies 2.10 (2019): 1900045