Sliding Ferroelectricity in a Bulk Misfit Layer Compound (PbS)_{1.11}VS_{2}.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Chemistry

Background:

• Twisted heterostructures of 2D crystals create moiré patterns, altering material properties.
• Misfit layer compounds offer a unique platform for generating moiré superlattices.

Purpose of the Study:

• To utilize alternated stacking in misfit layer compounds as a moiré generator.
• To investigate the induced electrical properties, specifically sliding ferroelectricity, in these twisted heterostructures.

Main Methods:

• Fabrication of misfit layer compounds with alternated stacking of posttransition metal monochalcogenides and transition metal dichalcogenides.
• X-ray diffraction to confirm the presence of twins and determine twist angles.
• Scanning probe microscopy and electron microscopy to visualize surface electrical potential and ferroelectric domains.

Main Results:

• X-ray diffraction confirmed the presence of twins with small twist angles, indicative of moiré generation.
• Scanning probe and electron microscopy revealed surface electrical potential due to induced sliding ferroelectricity.
• Ferroelectric domains were observed with sizes extending up to tens of micrometers.

Conclusions:

• Alternated stacking in misfit layer compounds effectively generates moiré patterns.
• This moiré generation induces sliding ferroelectricity in the heterostructures.
• The observed ferroelectric domains demonstrate the potential for novel electronic applications.