Intercorrelated ferroelectrics in 2D van der Waals materials

TL;DR

This paper introduces a novel scheme using van der Waals interactions to realize 2D intercorrelated ferroelectrics in a wide range of layered materials, enabling coupled in-plane and out-of-plane ferroelectricity.

Contribution

It proposes a new approach to achieve 2D intercorrelated ferroelectrics across many materials using first-principles calculations.

Findings

Multiple 2D vdW materials can exhibit coupled ferroelectricity.

Electrical control of spin textures demonstrated in trilayer PtSe2.

Electrical control of valley physics in four-layer VS2.

Abstract

2D intercorrelated ferroelectrics, exhibiting a coupled in-plane and out-of-plane ferroelectricity, is a fundamental phenomenon in the field of condensed-mater physics. The current research is based on the paradigm of bi-directional inversion asymmetry in single-layers, which restricts 2D intercorrelated ferroelectrics to extremely few systems. Herein, we propose a new scheme for achieving 2D intercorrelated ferroelectrics using van der Waals (vdW) interaction, and apply this scheme to a vast family of 2D vdW materials. Using first-principles, we demonstrate that 2D vdW multilayers-for example, BN, MoS2, InSe, CdS, PtSe2, TI2O, SnS2, Ti2CO2 etc.- can exhibit coupled in-plane and out-of-plane ferroelectricity, thus yielding 2D intercorrelated ferroelectricsferroelectric physics. We further predict that such intercorrelated ferroelectrics could demonstrate many distinct properties, for example, electrical full control of spin textures in trilayer PtSe2 and electrical permanent control of valley-contrasting physics in four-layer VS2. Our finding opens a new direction for 2D intercorrelated ferroelectric research.