Design Guidelines of Magnetic Tunnel Junctions with Two-dimensional Tunneling Barrier Layer: Atomistic Simulation Study from Material to Device

Abstract

Based on density functional theory (DFT) and non-equilibrium Green's function (NEGF) formalism, the magnetic tunnel junctions (MTJs) with 2D tunneling barrier (TB) material are systematically simulated from the material level to the device level. The magnetic properties of ferromagnetic metal (FM), spin-orbit coupling (SOC) of 2D TB, tunneling magnetoresistance (TMR) and I-V characteristics of MTJs are thoroughly studied. The effects of TB doping and interfacial layer (IL) engineering are discussed. We pointed out for the first time that 2D FM Fe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> FeTe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (FGT) and 2D semiconductors contacts can form good <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$n$</tex> -type contacts with lower Schottky barrier (SBH), especially the SBH is almost zero in FGT-InSe interface. More importantly, for the first time, it is found that each layer of FGT shows obvious perpendicular magnetic anisotropy (PMA) in FGT|WSe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> |FGT MTJ, which means that each layer of FGT used in MTJs contributes to the total MAE. On the other hand, MTJs using FGT can effectively suppress the minority-spin-transport channel and thus significantly improve TMR. In addition, graphene IL, TB doping and different TB layers are examined to further modulate TMR.