Thermal Transport Properties of Ho₂RhIn₈

The arrangement of the rare-earth atoms in the tetragonal structure of R₂TX₈ (R = rare earth, T = transition metal, X = In, Ga) takes a quasi two dimensional (2D) character. All of these compounds order antiferromagnetically with Neel temperatures (T_N) ranging between 4 – 45 K.  Ho₂RhIn₈ is one of the most interesting compounds among this very large family of closely related materials.

It shows two successive metamagnetic transitions at 2 K, when an external magnetic field is applied along the c axis. Its magnetic properties are driven mainly by crystalline electric effects and the RKKY interactions. We have grown single crystals of  Ho₂RhIn₈ and have studied these metamagnetic transitions through thermal and electrical transport properties. These transitions are absent in the Hall resistivity but they appear around the same fields in the thermal conductivity, thermal Hall conductivity, and the longitudinal electrical resistivity. We discuss these metamagnetic transitions and their relations to the possibility of the Ho₂RhIn₈ compound being a magnetic topological candidate.