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

Materials capable of switching in multiple states underexternalstimuli have garnered extensive attention in the field of memory devicesand switches. The coupling of various switching properties is of paramountsignificance to the creation of multifunctional devices. Herein, wereport the pressure-induced multiswitching behaviors of both the structuraland physical properties in two chromium selenides, CrSe and Cr2Se3. Comprehensive high-pressure characterizationsreveal the collaborative occurrence of pressure-induced structuralphase transitions, spin-crossover, metallization, and n-p conduction-type switching in both compounds.Upon compression, Cr2Se3 demonstrates an unexpectedincrease in resistivity and band gap, which is associated with thedisordering of the self-intercalation structure. Of particular interestis that due to the dimensional differences in crystal structures,the photoelectric properties of the two decompressed samples are inverselyregulated after pressure treatment. Notably, the band gap of Cr2Se3 is pronouncedly broadened after decompressiondue to the partially irreversible disorder in the structure. Theseresults demonstrate that pressure engineering can regulate the photoelectricproperties of materials effectively and flexibly, serving as a potentialfoundation for fabricating innovative pressure-responsive multifunctionaldevices.