Emergence of ferroelectricity and spin-valley properties in two-dimensional honeycomb binary compounds

TL;DR

This study predicts that certain two-dimensional honeycomb binary compounds exhibit ferroelectricity, spin-valley coupling, and switchable Rashba effects, revealing potential for novel electronic and spintronic applications.

Contribution

The paper introduces the prediction of ferroelectricity and controllable spin-valley properties in 2D AB binary monolayers using density functional theory.

Findings

Several AB monolayers are ferroelectric due to buckled structures.

Valley-dependent properties emerge from binary composition.

Reversing ferroelectric polarization switches Rashba spin textures.

Abstract

By means of density functional theory calculations, we predict that several two dimensional AB binary monolayers, where A and B atoms belong to group IV or III-V, are ferroelectric. Dipoles arise from the buckled structure, where the A and B ions are located on the sites of a bipartite corrugated honeycomb lattice with trigonal symmetry. We discuss the emerging valley-dependent properties and the coupling of spin and valley physics, which arise from the loss of inversion symmetry, and explore the interplay between ferroelectricity and Rashba spin-spitting phenomena. We show that valley-related properties originate mainly from the binary nature of AB monolayers, while the Rashba spin-texture developing around valleys is fully controllable and switchable by reversing the ferroelectric polarization.