Nonvolatile electrical control of valley splitting by ferroelectric polarization switching in a two-dimensional AgBiP₂S₆/CrBr₃ multiferroic heterostructure

Abstract

The generation and controllability of valley splitting is the major challenge to effectively utilize valley degrees of freedom in valleytronics. Using first-principles calculations, we propose a novel multiferroic system, AgBiP2S6/CrBr3...

Two-dimensional multiferroic RuClF/AgBiP2S6 van der Waals heterostructures with valley splitting properties and controllable magnetic anisotropy

“…These results are consistent with the previously reported studies. 38,40,42 In Fig. S1(a) and (b) (ESI †), the absence of imaginary frequencies in the phonon spectra of Janus RuClF and AgBiP 2 S 6 monolayers can confirm their dynamical stability at equilibrium.…”

“…Valley splitting at the edge of the conduction band structure is induced with SOC, and non-volatile control of valley splitting is achieved by changing the polarization direction of the FE layer in the CrBr 3 /AgBiP 2 S 6 heterostructure. 42 Conventional DFT fails for materials with strongly correlated electrons, such as the late transition metal oxide RuO 2 . 43 Large errors in the coulomb and exchange interactions within Ru atoms are responsible for this failure.…”

Valleytronics in two-dimensional magnetic materials

“…In addition to monolayer magnetic valleytronic materials, there are also a variety of magnetic valleytronic materials with multilayers [144][145][146][147] and those with magnetic substrate [148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163]. The valley spontaneous polarization occurs only when the magnetization has an out-of-plane component.…”

Recent progress on valley polarization and valley-polarized topological states in two-dimensional materials

“…[65] The details of the valley-polarized QAHE will be discussed in the next section. In recent years, there have been many works to realize the electrical control of valley DOF by forming heterostructures between multiferroic materials and other materials, [28,[66][67][68][69][70][71] such as AgBiP 2 S 6 /CrBr 3 vdW heterostructures with ferromagnetism, ferroelectricity and valley behavior. At the minimum of the conduction band located at the +K/ − K point, a spin splitting of 423.1 meV occurs.…”

“…The research on the non-volatile control of valley splitting in multiferroic heterostructures is of great theoretical significance and practical value for the design of integrated valley electronic devices. [71]…”