Resonant tunneling induced large magnetoresistance in vertical van der Waals magnetic tunneling junctions based on type-II spin-gapless semiconductor VSi2P4

Abstract

Rare type-II spin-gapless semiconductors (SGSs), in which electrons and holes are 100% spin polarized in different directions to the Fermi level, have attracted increasing attention. Motivated by the recent findings of type-II SGS VSi₂P₄ with ferromagnetic characteristics and a high Curie temperature (350 K), we investigated the interface contacts and spin transport properties of different devices composed of VSi₂P₄ ferromagnetic layers. It was found from the first-principles calculations combined with nonequilibrium Green's function that different potential barriers appear on the interface pinning and ultimately determine the conductive characteristics. The T-MoTe₂/VSi₂P₄/H-MoTe₂/VSi₂P₄/T-MoTe₂ device (1H device) shows a large tunnel magnetoresistance (TMR) of 3.35 × 10³% resulting from the interfacial spin filtering, and the T-MoTe₂/H-MoTe₂/VSi₂P₄/H-MoTe₂/VSi₂P₄/H-MoTe₂/T-MoTe₂ device (3H device) accompanied with many resonant states presents increased TMR (1.83 × 10⁴%). The transport properties of two devices are explained from the spin-dependent band structures, local density of states, transmission coefficients and eigenstates. These results indicate that VSi₂P₄ is a promising material for designing vertical van der Waals (vdW) heterostructures with a giant TMR in spintronic applications.