ELESIHS : ELectronic structure and Electrical Spin Injection in ferromagnetic Metal/Oxide/Semiconductor HYbrid Systems
Research project selected under the 2014 call for proposals
Principal Investigator :
Pierre Renucci ()
LPCNO (Quantum Optoelectronics Group (OPTO))
Type of project : Collaborative Project
Partner team(s) :
CEMES (Nmat (L. Calmels) + MC2 (C. Gatel))
Date (start/end) : 2015 - 2018
Figure. Left: Schematic device structure of a SpinLED with InGaAs/GaAs Quantum wells and a magnetic CoFeB/MgO injector by LPCNO and Co-workers (IJL-UMP Thalès-IOS)
Right: HR-TEM image of an ultrathin CoFeB/MgO PMA injector. Inset: lower magnification.
Abstract
The aim of Spintronics in Semiconductors is to use the electron spin as an additional degree of freedom to process information. It requires the injection of spin polarized currents into semiconductors. Up to now, researches have mostly focused on bulk semiconductors (3D) in which efficient spin injection through Ferromagnetic Metal/Crystalline MgO/Semiconductor (FM/MgO/SC) tunnel junctions has been obtained, but not fully understood. The aim of this project is to investigate the electron states at the FM/MgO/SC hybrid interfaces in order to make a breakthrough in the microscopic understanding of spin injection processes in semiconductors in view of clever interface engineering. First, we will study the CoFe(B)/MgO/GaAs(3D) system, by combining complementary techniques available in LPCNO and in CEMES: polarization-resolved Transport/optical techniques, density functional theory (DFT)-based calculations and high resolution transmission electron microscopy. Second, we will tackle the new challenge of electrical spin injection in two-Dimensional (2D) semiconductors based on Transition Metal Dichalcogenide (TMDC) like MoS 2 , MoSe 2 ,WSe 2 ... No experimental demonstration of this key step has been done yet in these 2D SCs.
Scientific objectives: Headlines goals of the ELESIHS project
- Investigation of the role played by bulk-like states and CoFe(B)/MgO and MgO/GaAs localized interface states on the electrical spin injection processes in the bulk GaAs, and analysis of the symmetry filtering of these states by the MgO/GaAs bilayer (LPCNO/CEMES nMat)
- Study of electron states in injectors presenting perpendicular magnetic anisotropy (PMA) for spin injection in 3D semiconductors without external magnetic field (LPCNO/CEMES nMat)
- Understanding of charge (and possibly spin) accumulation governing spin injection processes in GaAs-based bipolar spinLEDs devices (CEMES MC2)
- Demonstration of electrical spin injection in dichalcogenide two-dimensional semiconductors and microscopic understanding of the physical processes governing this injection (LPCNO/CEMES nMat)