Tunable spin polarization and electronic structure of bottom-up synthesized MoSi${}_2$N${}_4$ materials

Abstract

Manipulation of spin-polarized electronic states of two-dimensional (2D) materials under ambient conditions is necessary for developing new quantum devices with small physical dimensions. Here, we explore spin-dependent electronic structures of ultra-thin films of recently introduced 2D synthetic materials MSi${}_2$Z${}_4$ (M = Mo or W and Z = N or As) using first-principles modeling. Stacking of MSi${}_2$Z${}_4$ monolayers is found to generate dynamically stable bilayer and bulk materials with thickness-dependent properties. When spin-orbit coupling (SOC) is included in the computations, MSi${}_2$N${}_4$ monolayers display indirect bandgaps and large spin-split states at the $K$ and $K^{\prime }$ symmetry points at the corners of the Brillouin zone with nearly 100\% spin polarization. The spins are locked in opposite directions along an out-of-the-plane direction at $K$ and $K^{\prime }$, leading to spin-valley coupling effects. As expected, spin polarization is absent in the pristine bilayers due to the presence of inversion symmetry, but it can be induced via an external out-of-plane electric field much like the case of Mo(W)S${}_2$ bilayers. A transition from an indirect to a direct bandgap can be driven by replacing N by As in MSi${}_2$(N, As)${}_4$ monolayers. Our study indicates that the MSi${}_2$Z${}_4$ materials can provide a viable alternative to the MoS${}_2$ class of 2D materials for valleytronics and optoelectronics applications.

arXiv comment6 pages, 5 figures, Accepted version in PRB:Letters

References in corpus (25)

• Electric Field Effect in Atomically Thin Carbon Films
• Two-Dimensional Gas of Massless Dirac Fermions in Graphene
• Atomically thin MoS2: A new direct-gap semiconductor
• Experimental Observation of Quantum Hall Effect and Berry's Phase in Graphene
• Black phosphorus field-effect transistors
• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• 2D materials and van der Waals heterostructures
• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• Van der Waals density functionals applied to solids
• Valley contrasting physics in graphene: magnetic moment and topological transport
• Germanene: a novel two-dimensional Germanium allotrope akin to Graphene and Silicene
• Semiconducting Black Phosphorus: Synthesis, Transport Properties and Electronic Applications
• Polarity Reversed Robust Carrier Mobility in Monolayer MoS2 Nanoribbons
• Graphene valley filter using a line defect
• Dirac fermions in borophene
• PyProcar: A Python library for electronic structure pre/post-processing
• Valley susceptibility of an interacting two-dimensional electron system
• Valley-dependent properties of monolayer MoSi${}_2$N${}_4$, WSi${}_2$N${}_4$ and MoSi${}_2$As${}_4$
• Magnetic control of the valley degree of freedom of massive Dirac fermions with application to transition metal dichalcogenides
• Next-generation non-local van der Waals density functional
• Valley pseudospin in monolayer MoSi2N4 and MoSi2As4
• Strain-induced semiconductor to metal transition in MA2Z4 bilayers
• Reproduction of the charge density wave phase diagram in $1T$-${\mathrm{TiSe}}_2$ exposes its excitonic character
• Optomechanical measurement of thermal transport in two-dimensional MoSe2 lattices
• Gap opening and large spin-orbit splitting in MX2 (M=Mo,W X=S,Se,Te) from the interplay between crystal field and hybridizations: insights from ab-initio theory

Cited by in corpus (15)

• Limited ferromagnetic interactions in monolayers of MPS${}_3$ (M=Mn, Ni)
• Tunable electronic properties and band alignments of MoSi${}_2$N${}_4$/GaN and MoSi${}_2$N${}_4$/ZnO van der Waals heterostructures
• Floquet Engineering of Nonequilibrium Valley-Polarized Quantum Anomalous Hall Effect with Tunable Chern Number
• Two-dimensional MoSi2N4: An Excellent 2D Semiconductor for Transistors
• Protected valley states and generation of valley- and spin-polarized current in monolayer MA2Z4
• Coupled spin-valley, Rashba effect and hidden persistent spin polarization in WSi${}_2$N${}_4$ family
• Exploring the Structural Stability, Electronic and Thermal Attributes of synthetic 2D Materials and their Heterostructures
• Emergence of Rashba splitting and spin-valley properties in Janus MoGeSiP2As2 and WGeSiP2As2 monolayers
• Switchable large-gap quantum spin Hall state in two-dimensional MSi${}_2$Z${}_4$ materials class
• Probing the uniaxial strain-dependent valley drift and Berry curvature in monolayer MoSi${}_2$N${}_4$
• Fast electrically switchable large gap quantum spin Hall states in MGe${}_2$Z${}_4$
• Correlation-driven topological transition in Janus VSiGeP2As2
• Mott-Insulator Ca2RuO4 under a static external electric field
• Atomically thin obstructed atomic insulators with robust edge modes and quantized spin Hall effect
• Strain Modulated Electronic and Optical Properties of Laterally Stitched MoSi2N4/XSi2N4 (X=W, Ti) 2D Heterostructures