Sample Dependence in Structure and Magnetism of α-RuCl3

In this talk, we report our study on sample dependence in characterizations and structure of Kitaev candidate material, α-RuCl3. Previously, sample dependence in Neel temperature was observed with different magnetic structural periodicity [1]. Such difference in structural periodicity can naturally arise from stacking fault and samples with Tn=7K were associate with high qualities. However, even high-quality samples with Tn=7K can have varying Tn between Tn=6.5K to Tn=7.5K.

We investigate α-RuCl3 with different Tn using magnetic susceptibility, specific heat, and x-ray diffraction measurement. We find qualitative agreement between different samples in magnetic susceptibility and specific heat measurements. However, we observe difference in structure between different samples in diffraction measurement.

Structural transition is observed in all sample from monoclinic C2/m structure to R-3 structure below Ts=160K. However, for samples with different Tn, we find domain population to be different where some are single-domain while others are twinned. We associate minor difference in Tn around 7K arise from different stackings as well.

[1] A. Banerjee et al., Science 356, 1055-1059 (2022).