ИСТИНА

A comparative analysis of the properties of FeSe1−xTex crystals in the range of x values of about 0.4 and pure FeSe crystals is presented. We found that the anomaly in R (T) at the structural transition for the former differs significantly from the corresponding anomaly for the latter. This indicates a change in the type of the ground state in the studied compounds. Within the framework of the crystal field model, this can be explained as a consequence of a change in the distortion of the tetrahedral environment of iron, which leads to a change in the positions of the energy levels within t2g multiplet. Depending on the mutual position of the degenerate xz and yz levels and the xy level, the type of transition can change from orbital ordering to magnetic ordering.