Peculiar half-metallic state in zigzag nanoribbons ofMoS2: Spin filtering

Abstract

Layered structures of molybdenum disulfide (MoS 2) belong to a new class of two-dimensional (2D) semiconductor materials in which monolayers exhibit a direct band gap in their electronic spectrum. This band gap has recently been shown to vanish due to the presence of metallic edge modes when MoS 2 monolayers are terminated by zigzag edges on both sides. Here, we demonstrate that a zigzag nanoribbon of MoS 2 , when exposed to an external exchange field in combination with a transverse electric field, has the potential to exhibit a peculiar half-metallic nature and thereby allows electrons of only one spin direction to move. The peculiarity of such spin-selective conductors originates from a spin switch near the gap-closing region, so the allowed spin orientation can be controlled by means of an external gate voltage. It is shown that the induced half-metallic phase is resistant to random fluctuations of the exchange field as well as the presence of edge vacancies.

Point‐Defect‐Induced Half Metal in CrCl3 Monolayer

“…On the other hand, substantial efforts have been made to integrate novel properties of low dimensional materials since the synthesis of graphene . Thanks to the technologies of deposition and chemical exfoliation, a wide range of two‐dimensional(2D) compounds have been manufactured and reported to behave diversely compared with their bulk counterparts.…”

Edge states and spin-valley edge photocurrent in transition metal dichalcogenide monolayers

“…Appendix C: Derivation of kinetic equation (14) In order to derive the kinetic equation (14) we first write down the Hamiltonian of the system under consideration in terms of second-quantization operators: …”

“…(C5) and accounting for only contributions from poles at integration over time we arrive to a kinetic equation similar to that used in the main text (14):…”

“…As electron-electron scattering is very efficient in one dimension 28 and also due to possibility of relaxation in edge band via scattering by bulk phonons, we suppose that relaxation time within the edge band is of the same order. This allows us to solve the kinetic equation (14) in quasi-equilibrium approximation, which is justified when intra-band relaxation times is shorter than edge-bulk energy relaxation times. Therefore, we look for distribution function of the edge (valence) states in the form of Fermi-Dirac function with its own quasi Fermi-level µ e,τ (µ v,τ ).…”

Polarization-Driven Edge-State Transport in Transition-Metal Dichalcogenides

“…TMDs have strong spin-orbit coupling, large band gap and boundary metallicity compared with gapless graphene [8][9][10]. By manipulating edge states, such as strain engineering [11], applying electric field [12] and external exchange field [13], electronic properties of TMDs nanoribbons can be half-metallic [13], magnetic [14] and superconductive [15]. Topological superconductivity and Majorna zero-energy modes have been demonstrated based on edge states of monolayer MoS2 [15].…”