Designing double isolated bands and subgap states in two-dimensional XPS3 (X = Al,Ga,In,Tl) for achieving bi-anti-ambipolar transport

Anti-ambipolar transistors (AATs) are a promising candidate for multivalued logic devices, which are vital for improving the device density and data-handling capabilities of nanoelectronics. Compared with most AATs with \ensuremath{\Lambda}-shaped transport characteristics, the emerging four-logic-state bi-AATs have a stronger capability for exponentially increasing the integration density. Here, we demonstrate an alternative strategy to achieve bi-anti-ambipolar transport by using the intrinsic electronic properties of two-dimensional (2D) materials. In detail, by breaking symmetry in edge-sharing octahedra, 2D X${\mathrm{PS}}_{3}$ (X = $\mathrm{Al},\phantom{\rule{0.2em}{0ex}}\mathrm{Ga},\phantom{\rule{0.2em}{0ex}}\mathrm{In},\phantom{\rule{0.2em}{0ex}}\mathrm{Tl}$) materials exhibit isolated band structures with subgap states near the Fermi level. More importantly, this special electronic feature inspires the design of double subgap tunnel field-effect transistors (TFETs) for realizing bi-anti-ambipolar transport. Through quantum transport simulations, we observe M-shaped I-V curves in the 2D ${\mathrm{InPS}}_{3}$ TFET, verifying the feasibility of the device concept. This work broadens the horizon for the development of bi-anti-ambipolar devices in the forthcoming era of big data.