Conventional ferroelectric tunnel junctions (FTJs) face inherent limitations in simultaneously achieving both a high tunneling electroresistance ratio (TER) and a low resistance-area product (RAP), hindering high-density, low-power, nonvolatile memory applications. This study overcomes this challenge by designing asymmetric FTJs based on a two-dimensional ${\mathrm{In}}_2{\mathrm{S}}_3/{\mathrm{Cu}}_2\mathrm{Se}$ heterostructure. Utilizing first-principles calculations with quantum transport simulations, we demonstrate that ferroelectric polarization switching in ${\mathrm{In}}_2{\mathrm{S}}_3$ reversibly modulates the heterostructure's band alignment between type-III (metallic) and type-II (semiconducting) states. Exploiting this, we engineered asymmetric ${\mathrm{In}}_2{\mathrm{S}}_3/{\mathrm{Cu}}_2\left({\mathrm{Se}}_{0.9}{\mathrm{S}}_{0.1}\right)$ and ${\mathrm{In}}_2{\mathrm{S}}_3/{\mathrm{Cu}}_2\left({\mathrm{Se}}_{0.9}{\mathrm{Te}}_{0.1}\right)$ electrodes flanking a central ${\mathrm{In}}_2{\mathrm{S}}_3/{\mathrm{Cu}}_2\mathrm{Se}$ barrier. The asymmetric FTJ achieves a TER of $9.95\times {10}^8\%$, which is 5 orders of magnitude higher than that of symmetric FTJs ($1.28\times {10}^3\%$), while maintaining an ultralow RAP of $0.11\mathrm{\Omega }\mu {\mathrm{m}}^2$. Crucially, these optimal performance metrics (TER $\sim {10}^9\%$, $\mathrm{RAP}<0.2\mathrm{\Omega }\mu {\mathrm{m}}^2$) persist robustly even under variations in channel width ($N=1$ to $N=9$, $\sim 0.7–6.3\mathrm{nm}$) or electrode doping concentration (5%–15%). These findings highlight the superior performance and exceptional robustness of the asymmetric ${\mathrm{In}}_2{\mathrm{S}}_3/{\mathrm{Cu}}_2\mathrm{Se}$-based FTJ, which holds significant promise for high-density, low-power, nonvolatile memory applications.

Close

PrevNext

View figure in article

• Ferroelectricity
• 2-dimensional systems
• First-principles calculations
• Green's function methods