Nonsaturated large magnetoresistance and transport dynamics in a n-doped cryogenic WS e 2 field-effect device

Interest in the two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) continues to intensify, driven by their suitable band gaps to supplant silicon as next-generation semiconductor materials. Among various TMDs, tungsten diselenide ($\mathrm{WS}{\mathrm{e}}₂$) is renowned for its superior electrical properties in carrier density and mobility under ambient conditions. Despite its notable attributes, the behavior of monolayer $\mathrm{WS}{\mathrm{e}}₂$ in the electron-doped regime under cryogenic conditions remains largely uncharted, particularly concerning its magnetotransport properties. In this study, we reveal the transport mechanisms of monolayer $\mathrm{WS}{\mathrm{e}}₂$ from high temperatures down to the cryogenic regime. As evident by Efros--Shklovskii variable-range hopping (E-S VRH) in the cryogenic regime, strong Coulomb interactions arise between electrons. Above 8 K, an uncommon nonsaturated quadratic large magnetoresistance (MR) can be explained by the wave-function shrinkage model, which is consistent with the E-S VRH transport mechanism. Notably, the nonsaturated quadratic large MR shows a magnitude up to 1740% at 13 T. These findings underscore the potential applications for monolayer $\mathrm{WS}{\mathrm{e}}₂$ in cryogenic field-effect devices, magnetic sensors, and memory devices and mark a significant advance in magnetotransport research.