Elsevier

Materials Today Physics

Volume 27, October 2022, 100803
Materials Today Physics

Tunning magnetism and anisotropy by ferroelectric polarization in 2D van der Waals multiferroic heterostructures

https://doi.org/10.1016/j.mtphys.2022.100803Get rights and content

Highlights

The highlights of this work are:

  • 1.

    Our α-RuCl3/CuInP2S6 HS endows with highly tunable magnetic properties. α-RuCl3 was tuned to ferromagnetic state from proximate quantum spin-liquid state that the ferromagnetic and antiferromagnetic phase are nearly degenerate by ferroelectric control of the next nearest neighbor exchange coupling.

  • 2.

    The switching of polarization in CuInP2S6 leads to Ru ion orbital reconfiguration and the switching of the easy axis of magnetization from in-plane to out-of-plan. This makes Ru ions exhibit large perpendicular magnetic anisotropy, which not only can effectively stabilize the long-range magnetic ordering, but also enable the 2D easy axis ferromagnetic α-RuCl3 more advantageous in functionality for practical applications.

  • 3.

    Monte Carlo simulation verified that the ferromagnetic Tc of α-RuCl3/CuInP2S6 HS with upward polarized state is enhanced to 89 K, far exceeding CrI3 (45 K) and free-standing α-RuCl3 monolayer (17 K), which provides a promising platform for advance in low-dimensional magnetoelectric physics and spintronics applications.

Abstract

Since the successful exfoliation of two-dimensional (2D) magnetic CrI3 film, an increasing interest of research is the 2D analog of fascinating physical property of 3D material, of which the most attractive for both fundamental research and practical applications is the achieving effective magnetoelectric coupling and manipulation in 2D van der Waals (vdW) multiferroic heterostructure (HS). Herein, we report the discovery of ferroelectrically tunable orbital reconstruction in α-RuCl3/CuInP2S6 2D vdW HSs, enabling the remarkable transitions of magnetic ordering from proximate quantum spin-liquid state to ferromagnetic as well as the easy magnetization axis tuning from in-plane to out-of-plane direction. In addition, Monte Carlo simulation verified that, α-RuCl3 would transform into a perpendicular ferromagnetic material with Curie temperature of 89 K when the ferroelectric polarization points to α-RuCl3. Furthermore, by analyzing the density of states and the d-orbital-resolved magnetocrystalline anisotropy energy (MAE) of Ru atoms based on the second-order perturbation theory we elucidate that the contribution to MAE from the spin-orbit coupling interaction between d orbitals of Ru atoms show a transition from positive to negative, and ultimately dominating the MAE variation from easy-plane to easy-axis magnetization upon the reversible FE polarization. Therefore, the CuInP2S6 nonvolatile ferroelectric switching enables the nonvolatile electrical control of magnetic ordering and anisotropy. This work paves the way for exploring high-efficiency nanodevices and nonvolatile information storage based on the multiferroic 2D vdW HSs.

Section snippets

Credit author statement

Wenxuan Wang, Conceptualization, Methodology, Writing - Original Draft, Writing - Review & Editing. Wei Sun, Investigation, Software, Data Curation. Hang Li, Supervision, Funding acquisition. Xiaoning Li, Validation, Visualization. Zheyin Yu, Validation. Ying Bai, Review. Fengzhu Ren, Writing - Review & Editing. Hongyang Zhao, Review. Jianli Wang, Review. Zhenxiang Cheng: Supervision, Conceptualization, Writing - Review & Editing.

Methods

First-principles calculations were performed using the VASP package based on the projected augmented wave pseudopotentials [33,34]. The generalized gradient approximation (GGA) was considered as exchange-correlation functional including a U correction for Ru d-orbitals (GGA + U, U = 2.4 eV and J = 0.4 eV) [35,36]. And we took the van der Waals corrections as parameterized in the semiempirical DFT-D3 method into consideration for all the configurations [37]. The first Brillouin zone is sampled

Results and discussions

We implemented total energy spin polarization calculations to explore the magnetic ground state of monolayer α-RuCl3, including FM, AFM-Néel, AFM-zigzag, and AFM-stripy phases, and the corresponding spin structures are shown in Fig. 1. The relative energies of the four magnetic phases are summarized in Table S1 (See supplementary material). Here, the computation results show that the AFM-zigzag phase of RuCl3 monolayer is the ground state with magnetic moment of 1 μB and an easy plane

Summary

In conclusion, using first-principles calculation, we exploited the 2D vdW α-RuCl3/CuInP2S6 HSs as the platform hosting a robust ME coupling effect. By switching the CuInP2S6 FE polarization, the next-neighbor exchange interactions and anisotropy of α-RuCl3 was modified, then further enable the α-RuCl3 transformed from easy plane AFM to easy axis FM ordering, making the 2D easy axis FM α-RuCl3 more advantageous in functionality for practical applications. The elaborated investigation suggests

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

We acknowledge grants from the National Natural Science Foundation of China (Nos. 51571083, 11674083 and 52102238) and the Foundation of Postgraduate Education Innovation and Quality Improvement Project of Henan University (No. CX3040A0960115, CJ3050A0670499, CJ3050A0670524). H. Li acknowledges support from Henan University (Grant No. CJ3050A0240050) and the National Natural Science Foundation of China (Grant No. 11804078). Z.X. Cheng thanks the Australian Research Council for support (

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