# Boosting the Edelstein effect of two-dimensional electron gases by ferromagnetic exchange

**Authors:** Gabriel Lazrak, Börge Göbel, Agnès Barthélémy, Ingrid Mertig, Annika Johansson, Manuel Bibes  
**arXiv:** [2310.03348](https://arxiv.org/abs/2310.03348)  
**Date:** 2023-10-05  
**Summary page:** https://www.summarizepaper.com/en/paper/2310.03348v1/

## Key points

- Study focuses on enhancing the Edelstein effect in 2DEGs using ferromagnetic exchange coupling
- Strontium titanate (SrTiO$_3$) 2DEGs possess finite Rashba spin-orbit coupling for charge-spin interconversion
- Effects are more pronounced at low temperatures and become modest at room temperature
- Researchers utilize ferromagnetic exchange coupling to improve conversion efficiency
- Experimental band structure of non-magnetic SrTiO$_3$ 2DEGs used as starting point
- Out-of-plane Zeeman term introduced to mimic magnetic exchange coupling in tight-binding model
- Increasing internal magnetic fields enhances conversion efficiency by nearly one order of magnitude
- Conversion efficiency initially increases with magnetic field, reaches maximum value, then decreases due to competition between exchange coupling and effective Rashba interaction
- Enhancing band pair splitting amplifies Edelstein effect, weakening in-plane Rashba-type spin texture reduces it
- Magnetic properties can be utilized to enhance spin-charge interconversion in 2DEGs
- Introducing ferromagnetic exchange coupling significantly boosts conversion efficiency in SrTiO$_3$ 2DEGs for charge-spin interconversion through direct and inverse Edelstein effects
- Findings contribute to understanding how magnetic properties can enhance spin-charge interconversion in materials with potential applications in spintronics and quantum computing.

## Summary

The study focuses on enhancing the Edelstein effect in two-dimensional electron gases (2DEGs) by introducing ferromagnetic exchange coupling. Strontium titanate (SrTiO$_3$) 2DEGs possess a finite Rashba spin-orbit coupling, allowing for the interconversion of charge and spin currents through direct and inverse Edelstein effects. However, these effects are more pronounced at low temperatures and become modest at room temperature. To improve the conversion efficiency, researchers utilize ferromagnetic exchange coupling in 2DEGs. They begin with the experimental band structure of non-magnetic SrTiO$_3$ 2DEGs and introduce an out-of-plane Zeeman term in a tight-binding model to mimic magnetic exchange coupling. By increasing internal magnetic fields, they calculate the band structure and spin textures and compute the Edelstein effect using a semiclassical Boltzmann approach. The results show that making 2DEGs ferromagnetic enhances the conversion efficiency by nearly one order of magnitude. Initially, as the magnetic field increases, the conversion efficiency also increases significantly but reaches a maximum value before decreasing again. This behavior is attributed to the competition between exchange coupling and effective Rashba interaction. The researchers find that enhancing the splitting of band pairs amplifies the Edelstein effect while weakening the in-plane Rashba-type spin texture reduces it. These findings provide insights into how magnetic properties can be utilized to enhance spin-charge interconversion in 2DEGs. In conclusion, this study demonstrates that introducing ferromagnetic exchange coupling in SrTiO$_3$ 2DEGs can significantly boost their conversion efficiency for charge-spin interconversion through direct and inverse Edelstein effects. The findings contribute to our understanding of how magnetic properties can be harnessed to enhance spin-charge interconversion in materials with potential applications in spintronics and quantum computing.