Spin manipulation in semiconductor spin devices

• Applicant: Professor Dr. Mariusz Ciorga
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 429749589

The main goal of this project is to demonstrate control of the resistance of a lateral semiconductor device by electrical manipulation of the spins in the channel between ferromagnetic source and drain contacts. This will constitute then a full realization of the concept of Datta-Das spin field effect transistor (sFET), envisioned in 1990. In our previous work, we have realized single building blocks of the sFET, namely we have shown very efficient electrical spin injection into a semiconductor two-dimensional electron gas (2DEG) and we have shown that high magnetoresistance signals up to 80% can be observed in such devices. We have therefore all ingredients at hand to pursue the full realization of the Datta-Das concept. To this end, we plan to focus on two topics. Firstly, we are going to explore electrical spin injection and spin transport in quasi one-dimensional (1D) channels. Such a channel, although with only one transport mode, was invoked in the original Datta-Das proposal. Our devices constitute a perfect test bed to investigate the expected suppression of Dyakonov-Perel spin relaxation in quasi 1D channels, for electrically injected in-plane spins. This has been studied before for out-of-plane spins using optical methods. Secondly, we are going to directly address the crucial functionality of the sFET, i.e., electrical control of the spin precession via spin orbit coupling (SOC), in lateral local devices, with a spin-polarized current flowing between source and drain contacts. Apart from the original geometry proposed by Datta and Das, with a metal gate on top of the channel, we plan to explore here also the possibility of using lateral spin orbit coupling, originating from the lateral confinement in 1D channels, to induce and control spin precession.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr. Dominique Bougeard; Professor Dr. Dieter Weiss