Pressure-Induced Reversible and Irreversible Multistate Switching in NiAs-Type Chromium Selenides

Materials capable of switching in multiple states under external stimuli have garnered extensive attention in the field of memory devices and switches. The coupling of various switching properties is of paramount significance to the creation of multifunctional devices. Herein, we report the pressure-induced multiswitching behaviors of both the structural and physical properties in two chromium selenides, CrSe and Cr 2 Se 3 . Comprehensive high-pressure characterizations reveal the collaborative occurrence of pressure-induced structural phase transitions, spin-crossover, metallization, and n – p conduction-type switching in both compounds. Upon compression, Cr 2 Se 3 demonstrates an unexpected increase in resistivity and band gap, which is associated with the disordering of the self-intercalation structure. Of particular interest is that due to the dimensional differences in crystal structures, the photoelectric properties of the two decompressed samples are inversely regulated after pressure treatment. Notably, the band gap of Cr 2 Se 3 is pronouncedly broadened after decompression due to the partially irreversible disorder in the structure. These results demonstrate that pressure engineering can regulate the photoelectric properties of materials effectively and flexibly, serving as a potential foundation for fabricating innovative pressure-responsive multifunctional devices.