Spin-polarized transport in hydrogen-passivated graphene and silicene nanoribbons with magnetic transition-metal substituents

Abstract

We present a systematic theoretical study of the electronic transport in hydrogen passivated zigzag graphene and silicene nanoribbons with between zero and four neighboring H atoms on one edge replaced by magnetic transition metals (Fe, Co, and Ni). The calculations were performed using equilibrium transport and density-functional theory with the generalized gradient approximation to exchange and correlation. We considered the magnetic moments of the two edges aligned both ferromagnetically (Ferro-F form) and antiferromagnetically (Ferro-A form). The Ferro-A graphene-based ribbons were all semiconducting and would support moderate spin-polarized currents of either sign by applying positive or negative gate voltages. The Ferro-F graphene-based ribbons were all metallic; the most interesting for possible spintronic applications being that with a single Ni atom, in which strong spin-filtering at low bias resulted from a deep trough in the transmission of one spin component around the Fermi level. By contrast, in the Si-based analog this trough was split, partially eliminating the polarization of the current. This splitting was found to be related to the buckled structure of the Si-based nanoribbon, which has its origin in its preference for sp(3)-like hybridization.

Fundamental properties of alkali-intercalated bilayer graphene nanoribbons

“…Among passivated atoms, hydrogen is reportedly the best theoretically; however, oxygen is highly considered in experiments. 5,16,17,19,20,36,37,[55][56][57][58] Due to the difference in chemical bonds and interactions with the edges, possible arrangements 59 of edge structures were considered in both zigzag and armchair ribbons for both hydrogen and oxygen passivation. According to edge-formation energy per unit cell length, the distinct optimized zigzag and armchair H-and O-GNRs of the monolayer are shown in Fig.…”

“…Moreover, despite this H-GNRs are well studied theoretically, and predictions are not consistent with one another related to the existence of magnetism and the planar/non-planar geometry. 6,36,37 Thus, more complete and accurate results are required to clearly identify the stacking-induced diverse behaviors in O-and H-passivated bilayer GNRs.…”

Exfoliable and self-healable two-dimensional materials from wurtzite zinc chalcogenides as building blocks of nanodevices

“…Most of the theoretically anticipated two-dimensional (2D) materials with high percentage of surface atoms have been obtained by exfoliation of van der Waals crystals and have sparked worldwide interest owing to their novel properties and potential applications in different fields ranging from electronics to medicine. [1][2][3][4][5][6][7][8][9][10][11][12] Although van der Waals materials often bring on a wealth of innovative applications, their species are still only limited to layered compounds. Recently, there has been growing interest in fabricating synthetic 2D crystals that have no layered bulk analogues.…”

Spin filter properties of armchair graphene nanoribbons with substitutional Fe atoms

“…Several computational studies have focused on the spin filtering effect of zigzag graphene nanoribbons (zGNRs) [13][14][15]. These systems exhibit a magnetic ground state [16][17][18].…”

“…A recent study extended this research to silicene nanoribbons, employing Fe, Co, and Ni as transmission metal impurities, and including the relative orientation of their magnetic moments as an additional degree of freedom [15].…”