Spontaneous formation of Cr$_2$S$_3$ phase inclusions in a two-dimensional layered semiconductor CrSBr

Variations in the physical properties of two-dimensional semiconductors due to different growth conditions and random changes in stoichiometry are a problem for their use. We analyzed the chemical composition and physical properties of two commercially grown CrSBr samples and found differences in magnetic and optical properties that can be explained by crystal heterogeneity. A strong bromine deficiency was observed in one of the samples, which led to a shift in the critical transition temperature to the metamagnetic state from 132 K in the perfect sample to 120 K in the nonstoichiometric sample. The critical temperature of 120 K, as well as the local X-ray diffraction spectra, are consistent with the parameters characteristic of the Cr$_2$S$_3$ phase, which coexists with the primary CrSBr phase.