Lateral interfaces of transition metal dichalcogenides: A stable tunable one-dimensional physics platform

Abstract

We study in-plane lateral heterostructures of commensurate transition-metal dichalcogenides, such as MoS2-WS2 and MoSe2-WSe2, and find interfacial and edge states that are highly localized to these regions of the heterostructure. These are one-dimensional (1D) in nature, lying within the bandgap of the bulk structure and exhibiting complex orbital and spin structure. We describe such heteroribbons with a three-orbital tight-binding model that uses first principles and experimental parameters as input, allowing us to model realistic systems. Analytical modeling for the 1D interfacial bands results in long-range hoppings due to the hybridization along the interface, with strong spin-orbit couplings. We further explore the Ruderman-Kittel-Kasuya-Yosida indirect interaction between magnetic impurities located at the interface. The unusual features of the interface states result in effective long-range exchange non-collinear interactions between impurities. These results suggest that transition-metal dichalcogenide interfaces could serve as stable, tunable 1D platform with unique properties for possible use in exploring Majorana fermions, plasma excitations and spintronics applications.

Lateral heterostructures and one-dimensional interfaces in 2D transition metal dichalcogenides

“…(+ H.c.), where γ labels the atoms on both sides of the interface. The scaling factor δ describes the compositional symmetry as well as possible relaxation effects at the interface (it is found that δ = 0.1 is a value consistent with experiments [119]). The geometric average, with similar results for the state localization at the interface, uses t as the effective interface hoppings [118].…”

“…where A(B) are the TMDs on either side of the interface. This is analogous to the approach in [119]. Strain tensor.-Recently, the 2D strain tensor in lateral WSe 2 -MoS 2 HSs has been characterized as [36] = aa ab ba bb ,…”

“…The interface has moreover been recently proposed to serve as 1D-like host for long-range non-collinear magnetic interactions when magnetic impurities are hybridized to the interface, finding large tunability and stable conditions for the interaction to occur [119]. This is further described in section 3.2.2.…”

“…Tight-binding structure of commensurate TMD HSs.-Other approaches have also been used to describe the electronic structure of HSs. Tight-binding approaches have been among the most common, for either commensurate [118,119] or incommensurate HSs [120]. In this approach, it also becomes straightforward to model vacancies, adatoms and other local defects.…”

Spin-valley system in a gated MoS2-monolayer quantum dot

“…Transistor structures with TMDC monolayer forming active area in tunnel FETs are being developed [25], also with vertical TMDCs heterostructures [26,27]. The more intriguing lateral, in-plane TMDCs heterojunctions are also constructed, enabling interesting 1D physics at interfaces [28], or leading to improved FETs switching characteristics [29][30][31].…”