Summary:

At the crossroads of three solid state physics research field – spintronics, ferroelectricity and quantum materials – the CONTRABASS project aims to demonstrate the possibility to generate, manipulate and detect pure spin currents by the mean of an electric field in a non-volatile way, without the use of magnetic materials. The goal is to succeed in creating a new technology for information processing that overcomes the limitations of current electronics in terms of operating speed, size and especially energy consumption.

The CONTRABASS project proposes to simultaneously take advantage of the non-volatility of electrical polarization (ferroelectricity), by detecting its state through pure spin currents that are not dissipative and their conversion into charge current. The absence of inversion symmetry in ferroelectric materials allows a spin splitting of the conduction bands by Rashba effect (Fig. a) in their volume or, stacked with layers of material with strong Spin-Orbit Coupling, at their interface. With the strong electrical field induced by the electrical polarization, it is possible to electrically control the amplitude and sign of the Rashba coupling in such materials. It is thus possible to strongly modulate the interconversion rate between pure spin current and charge current (Fig. b) and thus to detect the state of the remanent ferroelectric polarization. Architectures based on this principle will offer a new approach to control pure spin currents by electric fields. In this project, the role of the IJL’s NanoMagnetism and Spin Electronics team will be to quantify the efficiency of the spin current – charge current

Funding: 120 000€ (IJL) / 550 000€ (Total)

Scientific project timeline: 01/01/2021 – 30/06/2025

IJL members: Sébastien Petit-Watelot, Carlos Rojas-Sanchez, Olivier Copie