Electronic transport in disordered MoS2 nanoribbons

Abstract

We study the electronic structure and transport properties of zigzag and armchair monolayer molybdenum disulfide nanoribbons using an 11-band tight-binding model that accurately reproduces the material's bulk band structure near the band gap. We study the electronic properties of pristine zigzag and armchair nanoribbons, paying particular attention to the edges states that appear within the MoS2 bulk gap. By analyzing both their orbital composition and their local density of states, we find that in zigzag-terminated nanoribbons these states can be localized at a single edge for certain energies independent of the nanoribbon width. We also study the effects of disorder in these systems using the recursive Green's function technique. We show that for the zigzag nanoribbons, the conductance due to the edge states is strongly suppressed by short-range disorder such as vacancies. In contrast, the local density of states still shows edge localization. We also show that long-range disorder has a small effect on the transport properties of nanoribbons within the bulk gap energy window.

Staircase-like transfer characteristics in multilayer MoS2 field-effect transistors

“…It is known that the conducting channel of MoS 2 FETs is formed initially at the edges and then expands to the entire flake [14]. This has been understood by the presence of topologically trivial electronic states localized at the edges [15,16], which are first populated by the gating [14]. Besides, the finite channel width of actual FETs also leads to the channel formation initially at the edges.…”

Disordered Si:P nanostructures as switches and wires for nanodevices

“…(2), G r (G a ) is the retarded (advanced) Green's function of the complete system (nanoribbon and leads), which we compute using the recursive Green's function approach, implemented as in Refs. [11,14,15]. The nth line or decay width, matrix elements Γ n = i[Σ r n − (Σ r n ) † ] are obtained from the embedding self-energy Σ r n = V † n G r n V n , where V n contains the coupling matrix elements of the sample with the nth lead, while G r n is the contact Green's function.…”

Efficient method for computing the electronic transport properties of a multiterminal system

“…In this Section we present in a nutshell the main results of the Landauer-Büttiker approach to calculate the transport properties of a multi-probe quantum coherent mesoscopic system. The RGF method can be imple- mented for both a finite element discretization of the Schrödinger equation [13,14] or a tight-binding model based on a linear combination of atomic orbitals [15,16]. For simplicity, in this paper we consider nearest neighbor tight-binding models that use a single orbital per site.…”