Magnetism and transport properties of zigzag graphene nanoribbons/hexagonal boron nitride heterostructures

Abstract

Results of ab initio study of magnetism and transport properties of charge carriers in zigzag graphene nanoribbons (ZGNR) on hexagonal boron nitride (h-BN(0001)) substrate are presented within the density functional theory framework. Peculiarities of the interface band structure and its role in the formation of magnetism and transport properties of the ZGNR/h-BN(0001) heterostructure have been studied using two different density functional approximations. The effect of the substrate and graphene nanoribbons width on the low-energy spectrum of π-electrons, local magnetic moments on atoms of interface, and charge carriers mobility in the ZGNR/h-BN(0001) heterostructures have been established for the first time. The regularity consisting in the charge carrier mobility growth with decrease of dimers number in nanoribbon was also established. It is found that the charge carriers mobility in the N-ZGNR/h-BN(0001) (N—number of carbon (C) dimers) heterostructures is 5% higher than in freestanding ZGNR.

Tuning the band structure, magnetic and transport properties of the zigzag graphene nanoribbons/hexagonal boron nitride heterostructures by transverse electric field

“…We have noted that, the substrate significantly varies magnetic and transport properties of ZGNRs. 38 In particular, it was also shown that the influence of the substrate on electronic properties of the heterostructure increases with decreasing GNR width. 38 In this study showed that the degeneration in energy of the edge localized states is removed when E ext is applied.…”

“…38 In particular, it was also shown that the influence of the substrate on electronic properties of the heterostructure increases with decreasing GNR width. 38 In this study showed that the degeneration in energy of the edge localized states is removed when E ext is applied. In ZGNR/h-BN(0001) heterostructure, value of this splitting energy was higher than one in ZGNRs without substrate.…”

“…This deformation cause sharp peaks corresponding to the electron density states in the proximity of the Fermi level and induces LMM at the ZGNR edges. 38 We used DFT calculations to establish the dependence of the LMM value at the GNRs edges upon the strength and direction of an E ext applied perpendicularly to the nanoribbon width. Figure 2 demonstrates LMM of the edge C atoms in 8-ZGNR without substrate (a) and on the h-BN(0001) substrate (b) depending on E ext .…”

Electronic Structure and Itinerant Magnetism of Hydrogenated Graphene Nanofilms

“…Usually, the ferromagnetic properties of these structures are associated with the presence of spin asymmetry of valence electrons, which is realized by two mechanisms: 1) impurities of other elements; 2) quasi-regular defects of the carbon structure (for example, graphene nanoribbons (GNR)) [9]. The boundary geometry is responsible for the spin density asymmetry at the GNR edges, which is confirmed by the results given in the works [10,11]. As exemplified by ZGNR/h-BN(0001) heterostructures , the spin magnetic moments (MM) of 0,27 B , are induced at the edges, which is more than an order of magnitude higher than that of other carbon atoms.…”

“…As exemplified by ZGNR/h-BN(0001) heterostructures , the spin magnetic moments (MM) of 0,27 B , are induced at the edges, which is more than an order of magnitude higher than that of other carbon atoms. The authors of [10,11] attributed the nature of magnetism to the violation of the symmetry breaking of the sublattices A and B of graphene caused by the deformation of the C-C bond length at the edges of the nanoribbon. It is known [12] that the magnetic state of graphene nanoribbons is characterized by a lower energy than the nonmagnetic state.…”