Occupancy disorder in the magnetic topological insulator candidate Mn1-xSb2+xTe4

MnSb2Te4 is a candidate magnetic topological insulator exhibiting more pronounced cation intermixing than its predecessor MnBi2Te4. Investigating the cation intermixing and its possible implications on the magnetic order in MnSb2Te4 are currently hot topics in research on quantum materials for spintronics and energy-saving applications. Two single-crystal X-ray diffraction measurements of Mn1-xSb2+xTe4 (x = 0.06 and x = -0.1) are presented alongside a detailed discussion of its crystal structure with a spotlight on the apparent occupancy disorder between the two cations. This disorder has been noted by other groups as well, yet never been analyzed in-depth with single-crystal X-ray diffraction. The latter is the tool of choice to receive a meaningful quantification of antisite disorder. Between the two synthesis procedures we find subtle differences in phases and/or alternation of the cation content which has implications on the magnetic order, as illustrated by bulk magnetometry. Understanding and assessing this disorder in magnetic topological insulators of the MnX2Te4 (X = Bi, Sb) type is crucial to gauge their applicability for modern spintronics. Furthermore, it opens new ways to tune the chemical composition - physical property relationship in these compounds, creating an alluring aspect also for fundamental science.

Automated summary

MnSb2Te4 is a candidate magnetic topological insulator with significant cation intermixing, which is being investigated through single-crystal X-ray diffraction for its implications on magnetic order. This study reveals apparent occupancy disorder between cations and subtle phase differences in the material, providing insights into tuning chemical composition and physical properties for spintronics applications. Understanding and analyzing this disorder is crucial for assessing the applicability of MnX2Te4 type materials in modern spintronics and energy-saving technologies.