Pressure-driven semiconductor-to-metal, magnetic, and structural transitions in the ferrimagnetic semiconductor Mn₃Si₂Te₆

Mn₃Si₂Te₆ is a ferrimagnetic nodal-line semiconductor with colossal angular magnetoresistance at ambient pressure. In this work, we investigated the effect of hydrostatic pressure on its electrical transport properties, magnetic transition, and crystal structure by measuring resistivity, DC and AC magnetic susceptibility, and XRD under various pressures up to ~ 20 GPa. Our results confirmed the occurrence of pressure-induced structural transition at P_c ≈ 10-12 GPa accompanied by a concurrent drop of room-temperature resistance in Mn₃Si₂Te₆. In the low-pressure phase at P < P_c, the ferrimagnetic transition temperature T_C increases linearly with pressure from ~75 K at ambient pressure to ~257 K at 10.8 GPa, and the semiconducting state is converted gradually to a metallic behavior at T < T_C. Accurate structural information in the low-pressure phase has been extracted from refinements of single-crystal XRD data, which help us to understand the dramatic enhancement T_C. In the high-pressure phase at P > P_c, the sample exhibits a metallic behavior in the whole temperature range and its resistivity exhibits a kink anomaly at T_M, characteristic of critical scattering around a magnetic transition. Recovery of the Raman spectrum upon decompression indicated that pressure-induced structural transition is reversible without amorphization under hydrostatic pressure conditions. Our present work not only resolves some existing controversial issues but also provides new insights into pressure-driven diverse behaviors of Mn₃Si₂Te₆.