Pressure-induced Structural Phase Transition, Metallization, and Superconductivity in layered metalloid dichalcogenide 1T-SiTe$_2$

Abstract

Layered transition-metal dichalcogenides (TMDs) have attracted considerable attention as promising platforms for exploring emergent physics and potential device applications. In contrast, metalloid-based dichalcogenide counterparts remain largely underexplored. Here, we report the pressure-induced structural phase transition, metallization, and superconductivity in the layered metalloid dichalcogenide 1T-SiTe$_2$. At ambient pressure, 1T-SiTe$_2$ crystallizes in a trigonal crystal structure (space group: $P\bar{3}m1$) and exhibits intrinsic semiconducting transport characteristics. Upon pressurization, in concomitant with the suppression of semiconducting behavior in resistance, superconductivity emerges at around 6.7 GPa. The superconducting transition temperature (T$_c$) rises continuously with increasing pressure and finally saturates at approximately 5.5 K for pressures above 30 GPa. During the compression, 1T-SiTe$_2$ experiences three structural phase transitions, and the phase transition pressures are highly consistent with the anomalous transport responses observed experimentally, indicating that the changes of transport behavior of 1T-SiTe$_2$ under pressure are structurally-driven. Our work extends TMD superconductors into the realm of metalloid systems and provides a new platform for exploring novel physics in quasi two-dimensional materials without transition-metal elements.