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High-Throughput Discovery of Two-Dimensional Materials Exhibiting Strong Rashba-Edelstein effect

Binchang Zhou, Baoru Pan, Pan Zhou, Yuzhong Hu, Songmin Liu, Lizhong Sun

TL;DR

This study addresses the limited understanding of the Rashba-Edelstein effect in two-dimensional materials by performing a symmetry-based classification of the REE tensor across all 80 layer groups, identifying 13 allowed tensor forms. Combining high-throughput screening of the C2DB database with first-principles calculations, the authors discover 54 candidate 2D materials with large charge-to-spin conversion efficiencies, greatly surpassing known values. They construct symmetry-constrained $k \cdot p$ models for three representative materials (HgI$_{2}$, AgTlP$_2$Se$_6$, BrGaTe) to reveal how specific spin textures at high-symmetry points drive the strong REE responses, including notable out-of-plane spin accumulations. The work establishes a systematic framework for discovering high-performance REE-driven CSC in 2D materials and highlights new material platforms for spintronic devices such as spin logic and SOT-based memory with low energy consumption.

Abstract

The Rashba-Edelstein effect (REE), which generates spin accumulation under an applied electric current, quantifies charge-to-spin conversion (CSC) efficiency in non-centrosymmetric systems. However, systematic investigations of REE in two-dimensional (2D) materials remain scarce. To address this gap, we perform a comprehensive symmetry analysis based on the 80 crystallographic layer groups, elucidating the relationship between materials' symmetries and the geometric characteristics of the REE response tensor. Our analysis identifies 13 distinct symmetry classes for the tensor and reveals all potential material candidates. Considering the requirement of strong spin-orbit coupling for a large REE response, we screen the C2DB database and identify 54 promising 2D materials. First-principles calculations demonstrate that the largest REE response coefficients in these materials exceed those reported for other 2D systems by an order of magnitude, indicating exceptionally high CSC efficiency. Focusing on three representative materials, including HgI2, AgTlP2Se6 and BrGaTe, we show that their large response coefficients can be well explained by effective kp models and the characteristic spin textures around high-symmetry points in momentum space. This work provides a systematic framework and identifies high-performance candidates, paving the way for future exploration of REE-driven CSC in 2D materials.

High-Throughput Discovery of Two-Dimensional Materials Exhibiting Strong Rashba-Edelstein effect

TL;DR

This study addresses the limited understanding of the Rashba-Edelstein effect in two-dimensional materials by performing a symmetry-based classification of the REE tensor across all 80 layer groups, identifying 13 allowed tensor forms. Combining high-throughput screening of the C2DB database with first-principles calculations, the authors discover 54 candidate 2D materials with large charge-to-spin conversion efficiencies, greatly surpassing known values. They construct symmetry-constrained models for three representative materials (HgI, AgTlPSe, BrGaTe) to reveal how specific spin textures at high-symmetry points drive the strong REE responses, including notable out-of-plane spin accumulations. The work establishes a systematic framework for discovering high-performance REE-driven CSC in 2D materials and highlights new material platforms for spintronic devices such as spin logic and SOT-based memory with low energy consumption.

Abstract

The Rashba-Edelstein effect (REE), which generates spin accumulation under an applied electric current, quantifies charge-to-spin conversion (CSC) efficiency in non-centrosymmetric systems. However, systematic investigations of REE in two-dimensional (2D) materials remain scarce. To address this gap, we perform a comprehensive symmetry analysis based on the 80 crystallographic layer groups, elucidating the relationship between materials' symmetries and the geometric characteristics of the REE response tensor. Our analysis identifies 13 distinct symmetry classes for the tensor and reveals all potential material candidates. Considering the requirement of strong spin-orbit coupling for a large REE response, we screen the C2DB database and identify 54 promising 2D materials. First-principles calculations demonstrate that the largest REE response coefficients in these materials exceed those reported for other 2D systems by an order of magnitude, indicating exceptionally high CSC efficiency. Focusing on three representative materials, including HgI2, AgTlP2Se6 and BrGaTe, we show that their large response coefficients can be well explained by effective kp models and the characteristic spin textures around high-symmetry points in momentum space. This work provides a systematic framework and identifies high-performance candidates, paving the way for future exploration of REE-driven CSC in 2D materials.
Paper Structure (8 sections, 6 equations, 5 figures)

This paper contains 8 sections, 6 equations, 5 figures.

Table of Contents

  1. Introduction
  2. Symmetry Analysis of the Rashba-Edelstein Tensor in Layer group
  3. Rules for Material Screening and Selection
  4. Representative material HgI$_2$
  5. Representative material AgTlP$_2$Se$_6$
  6. Representative material BrGaTe
  7. CONCLUSIONS
  8. METHODS

Figures (5)

  • Figure 1: The workflow of high-throughput screening process.
  • Figure 2: Distribution of materials according to LG with inversion symmetry broken. The background color coding refers to the crystal system (the monoclinic crystal system is further classified according to its lattice type). Part of the candidate materials from different categories are shown in the figure.
  • Figure 3: Structure and electronic properties of the HgI$_2$. (a) Top view and side view of 2D HgI$_2$. (b) Spin-polarized bands for $S_x$, $S_y$ spin projections of HgI$_2$ shown along the $M$ - $\Gamma$ - $X$ - $\Gamma$ path. (c) In-plane ST around $\Gamma$. ($S_x$, $S_y$) components are represented by the arrows. $S_z$ component is represented by the color.(d) Calculated $\chi_{xy}$ and $\chi_{yx}$ as a function of the chemical potential. Due to symmetry considerations, the component $\chi_{xy}$ is equivalent to $\chi_{yx}$. (e) The constant energy contour for $E = -0.946$ eV.
  • Figure 4: Computational analysis of monolayer AgTlP$_2$Se$_6$. (a) Top and side view of the crystal structure. (b) Spin-polarized energy bands with $S_x$, $S_y$ spin projections, plotted along the high-symmetry path. (c)-(d) The contour with the superimposed in-plane ST around $K$ and $K'$. ($S_x$, $S_y$) components are symbolized by the arrows. $S_z$ components are omitted. (e) The magnitude of the $\chi$ tensor is calculated as a function of the chemical potential. Symmetry analysis dictates that the component $\chi_{xx}$ is equal to $\chi_{yy}$.
  • Figure 5: The Structural and electronic characteristics of BrGaTe. (a) Top view and side view of the crystal structure. (b) Spin-polarized bands for $S_z$ spin projection calculated along the high symmetry path. (c) In-plane ST around $\Gamma$. ($S_x$, $S_y$) components are represented by the arrows and the normal component $S_z$ by the color. (d) Calculated magnitude of the REE as a function of the chemical potential. The only component that exists is $\chi_{zx}$. (e) The constant energy contour for $E = -0.631$ eV.