All‐Electrical Detection of the Spin‐Charge Conversion in Nanodevices Based on SrTiO₃ 2‐D Electron Gases

Abstract

The Magnetoelectric Spin‐Orbit (MESO) technology aims to bring logic into memory by combining a ferromagnet with a magnetoelectric (ME) element for information writing, and a spin‐orbit (SO) element for information read‐out through spin‐charge conversion. Among candidate SO materials to achieve a large MESO output signal, oxide Rashba two‐dimensional electron gases (2DEGs) have shown very large spin‐charge conversion efficiencies, albeit mostly in spin‐pumping experiments. Here, all‐electrical spin‐injection and spin‐charge conversion experiments in nanoscale devices harnessing the inverse Edelstein effect of SrTiO3 2DEGs are reported. Nanodevices aredesigned, patterned, and fabricated in which a spin current injected from a cobalt layer into the 2DEG is converted into a charge current. The spin‐charge conversion signal is optimized by applying back‐gate voltages and studied its temperature evolution. It further disentangles the inverse Edelstein contribution from spurious effects such as the planar Hall effect, the anomalous Hall effect, or the anisotropic magnetoresistance. The combination of non‐volatility and high energy efficiency of these devices can potentially lead to new technology paradigms for beyond‐CMOS computing architectures.

Second-order charge and spin transport in LaO/STO system in the presence of cubic Rashba spin orbit couplings

“…Various logic devices based on the dual control of the non-reciprocal charge transport by a gate voltage and the magnitude of the applied electrical field have been proposed in a very recent study [45]. In addition, the high charge-to-spin conversion efficiency of the LaO/STO system may be enhanced by the second-order response to improve the performance of scalable magnetoelectric spin-orbit devices [50], in which the combination of non-volatility and high energy efficiency can potentially lead to new paradigms for beyond-CMOS computing architectures [51]. Besides prospective device applications, it has also been suggested that the variation of the nonreciprocal charge current with the direction of the applied magnetic field can provide a means for determining the Rashba parameter of a 2DEG system [9].…”