Single crystal growths and magnetic properties of hexagonal polar semimetals AuGe ( = Y, Gd-Tm, and Lu)

Kurumaji, Takashi*; Gen, Masaki*; Kito, Shunsuke*; Ikeuchi, Kazuhiko*; Nakamura, Mitsutaka   ; Ikeda, Akihiko*; Arima, Takahisa*

We study structural and magnetic properties of rare-earth based semimetals AuGe ( = Y, Gd-Tm, and Lu) using flux-grown single crystals. We evaluate the crystal electric field parameters based on the Stevens operators to reasonably reproduce the temperature dependence of magnetic susceptibilities and specific heat for RAuGe ( = TbTm). The estimated energy scale of the Ising gap ( 11 meV) in TmAuGe is consistent with an excitation observed in an inelastic neutron scattering experiment. These findings suggest an opportunity for interplay between conduction electrons and nontrivial spin structures in the family of magnetic polar semimetals AuGe.