Electric control of spin injection into a ferroelectric semiconductor

TL;DR

This paper demonstrates that reversing ferroelectric polarization in a specific heterostructure significantly alters spin polarization of electron transmission, offering a new way to electrically control spin injection in spintronics devices.

Contribution

It provides first-principles evidence that ferroelectric polarization switching can modulate spin injection efficiency at a ferroelectric/ferromagnetic interface.

Findings

Reversal of ferroelectric polarization changes spin polarization from -65% to -98%.

Interface transmission is negatively spin-polarized.

Large difference in Fermi wave vectors influences transport regime.

Abstract

Electric-field control of spin-dependent properties has become one of the most attractive phenomena in modern materials research due the promise of new device functionalities. One of the paradigms in this approach is to electrically toggle the spin polarization of carriers injected into a semiconductor using ferroelectric polarization as a control parameter. Using first-principles density functional calculations, we explore the effect of ferroelectric polarization of electron-doped BaTiO3 (n-BaTiO3) on the spin-polarized transmission across the SrRuO3/n-BaTiO3 (001) interface. Our study reveals that the interface transmission is negatively spin-polarized and that ferroelectric polarization reversal leads to a change in the transport spin polarization from -65% to -98%. We show that this effect stems from the large difference in Fermi wave vectors between up- and down-spins in ferromagnetic SrRuO3 and a change in the transport regime driven by ferroelectric polarization switching. The predicted sizeable change in the spin polarization provides a non-volatile mechanism to electrically control spin injection in semiconductor-based spintronics devices.