Spin Transport Properties of zCrXY (X, Y = S,Se) Nanoribbons: Implications for Spintronics

CrXY (X, Y = S, Se) nanoribbons of the zigzag type (zCrXYNRs) are investigated as candidates for applications in nanospintronics. Density functional theory (DFT) in conjunction with a nonequilibrium Green’s function (NEGF) approach is used to model the magnetoresistance and spin-filtering properties of zCrS2NRs with five CrS2 rows (5-zCrS2NRs) as a function of longitudinal strain as well as vertical and lateral gate fields for ferromagnetic (FM) and antiferromagnetic (AFM) phases of the ribbon. In the bias regime V < 10 mV, magnetoresistance ratios up 107% were obtained, and half-metallicity was established for the magnetic ground state of 5-zCrS2NR (AFM), associated with magnetocurrent ratios of 100%. Applying lateral gate fields to the ribbon turned out to be a way of controlling the sign of the net spin population emerging from 5-zCrS2NR. Comparison is made with ribbons of the form 5-zCrSe2NRs and the Janus ribbon 5-zCrSeSNRs. The latter displays electronic and spin-resolved transport properties analogous to 5-zCrS2NR at 5% strain level and is therefore interpreted in terms of a zCrS2 ribbon with longitudinal strain.