Ferroelastic–Ferroelectric Multiferroicity in van der Waals Rhenium Dichalcogenides

Abstract

2D multiferroics with combined ferroic orders have gained attention owing to their novel functionality and underlying science. Intrinsic ferroelastic–ferroelectric multiferroicity in single‐crystalline van der Waals rhenium dichalcogenides, whose symmetries are broken by the Peierls distortion and layer‐stacking order, is demonstrated. Ferroelastic switching of the domain orientation and accompanying anisotropic properties is achieved with 1% uniaxial strain using the polymer encapsulation method. Based on the electron localization function and bond dissociation energy of the Re–Re bonds, the change in bond configuration during the evolution of the domain wall and the preferred switching between the two specific orientation states are explained. Furthermore, the ferroelastic switching of ferroelectric polarization is confirmed using the photovoltaic effect. The study provides insights into the reversible bond‐switching process and potential applications based on 2D multiferroicity.

Two-dimensional multiferroic material of metallic p-doped SnSe

“…In general, the electron spin order in partially filled d/f orbitals of transition metals results in the evolution of magnetism and breaks the time-reversal symmetry. However, the ferroelectricity often derives from the residual polarization due to the stable off-centered ion with empty d/f orbitals, which breaks the space-inversion symmetry 11 . In this regard, the exploration of multiferroic in low symmetry materials is promising and considerable efforts have also been made (e.g., NiI 2 1 , GaFeO 3 12 , BiFeO 3 13 , TbMnO 3 14 , and MnWO 4 15 , etc).…”

Structure modulation of two-dimensional transition metal chalcogenides: recent advances in methodology, mechanism and applications

“…69 Recently, exciting results of twinned boundary in 1T′′-ReS 2 have been reported, where the upward and downward Re chains are distributed in distinct grains separated by a twinned boundary. 70–72 The Re chains formed by the Re–Re metal bonds lying in different 1T′′-ReS 2 domains can further result in three types of twinned boundaries, including (0°, 0°) σ , (60°, 120°) σ and (120°, 240°) σ , as shown in Fig. 5(e)–(g), respectively.…”

Ferroic Phases in Two-Dimensional Materials

“…406 On the experimental side, Jeong et al observed the ferroelastic−ferroelectric multiferroicity in rhenium dichalcogenides (ReX 2 , X = S, and Se) using PFM and the photovoltaic effect. 339 Ferroelastic domain switching between equivalent orientation states (referred to as O1 and O2 in Figure 29c) was experimentally achieved using a polymer encapsulation approach under uniaxial strain (1%). Through polarized optical microscopy, they recorded the corresponding evolution of the domain structure under tensile strain, as shown in Figure 29d, strongly indicating 2D ferroelasticity in ReS 2 .…”