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

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Room-temperature ferroelectricity is crucial for next-generation electronics, including non-volatile memory and neuromorphic computing.
• Discovering ferroelectricity in 2D materials with natural central symmetry, especially at the atomic limit, is challenging.
• Existing 2D ferroelectric materials often lack stability or exhibit limited performance.

Purpose of the Study:

• To discover and characterize room-temperature ferroelectricity in a novel two-dimensional (2D) semiconductor.
• To investigate the mechanism behind ferroelectricity emergence in 2D materials.
• To evaluate the performance of 2D α-MnS in ferroelectric tunneling junctions.

Main Methods:

• Chemical vapor deposition (CVD) synthesis of 2D α-MnS.
• Analysis of material structure and strain evolution using microscopy and spectroscopy.
• Fabrication and characterization of ferroelectric tunneling junctions (FTJs) based on 2D α-MnS.

Main Results:

• Room-temperature ferroelectricity with out-of-plane polarization was observed in CVD-synthesized 2D α-MnS.
• Ferroelectricity originates from dislocations induced by thermal expansion mismatch between α-MnS and the mica substrate, causing tensile strain and sulfur atom displacement.
• The FTJ device demonstrated significant tunneling electroresistance (1.3 × 10^4), high endurance (2.8 × 10^3 cycles), and a retention time of 1 year.

Conclusions:

• 2D α-MnS is a promising material for achieving room-temperature ferroelectricity.
• Strain engineering via substrate interaction is an effective strategy for inducing ferroelectricity in 2D materials.
• This discovery paves the way for developing ultrahigh-density information storage and computing-in-memory devices.