S-atom dislocation-induced room-temperature ferroelectricity in two-dimensional α-MnS semiconductor.

Abstract

Room-temperature ferroelectricity in two-dimensional semiconductors has ignited enormous interests due to their potential applications in non-volatile memory and neuromorphic computing, which will trigger a revolution in next-generation electronics. Nonetheless, this fascinating ferroelectricity is rarely discovered in such materials with natural central symmetry, especially at atomically thin limit. Here we disclose a room-temperature ferroelectricity with out-of-plane polarization in chemical vapor deposition synthesized two-dimensional α-MnS. The difference in thermal expansion coefficients between α-MnS and mica substrate leads to the evolution of dislocations in two-dimensional α-MnS, which induce the generation of tensile strain and the displacement of S atoms, thereby result in the emergence of ferroelectricity. In addition, the ferroelectric tunneling junction based on two-dimensional α-MnS exhibits large tunneling electroresistance (1.3 × 10⁴), high endurance (2.8 × 10³ cycles), and long retention time (1 year). This work represents a substantial leap for developing two-dimensional ferroelectric semiconductors, which will stimulate the further exploration of ultrahigh-density information storage devices and computing-in-memory chips.