Band energy landscapes in twisted homobilayers of transition metal dichalcogenides

Abstract

Twistronic assembly of 2D materials employs the twist angle between adjacent layers as a tuning parameter for designing the electronic and optical properties of van der Waals heterostructures. Here, we study how interlayer hybridization, weak ferroelectric charge transfer between layers, and piezoelectric response to deformations set the valence and conduction band edges across the moir{é} supercell in twistronic homobilayers of MoS${}_2$, MoSe${}_2$, WS${}_2$ and WSe${}_2$. We show that, due to the lack of inversion symmetry in the monolayer crystals, bilayers with parallel (P) and anti-parallel (AP) unit cell orientations display contrasting behaviors. For P-bilayers at small twist angles we find band edges in the middle of triangular domains of preferential stacking. In AP-bilayers at marginal twist angles (${\theta }_{AP}<1^{\circ }$) the band edges are located in small regions around the intersections of domain walls, giving highly localized quantum dot states.

21 pages, 15 figures

References in corpus (11)

• Quantum ESPRESSO toward the exascale
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Stacking-engineered ferroelectricity in bilayer boron nitride
• Charge-polarized interfacial superlattices in marginally twisted hexagonal boron nitride
• Interlayer coupling in commensurate and incommensurate bilayer structures of transition metal dichalcogenides
• Revisiting the buckling metrology method to determine the Young's modulus of 2D materials
• Piezoelectric networks and ferroelectric moiré superlattice domains in twistronic WS${}_2$/MoS${}_2$ and WSe${}_2$/MoSe${}_2$ bilayers
• Flat bands, strains, and charge distribution in twisted-bilayer hBN
• Interferences of electrostatic moiré potentials and bichromatic superlattices of electrons and excitons in transition metal dichalcogenides
• Electron transport in dual-gated three-layer MoS${}_2$
• Flat band properties of twisted transition metal dichalcogenide homo- and heterobilayers of MoS${}_2$, MoSe${}_2$, WS${}_2$ and WSe${}_2$

Cited by in corpus (14)

• Rotational and Dilational Reconstruction in Transition Metal Dichalcogenide Moiré Bilayers
• Multifaceted moiré superlattice physics in twisted WSe${}_2$ bilayers
• Moire Potential, Lattice Relaxation and Layer Polarization in Marginally Twisted MoS2 Bilayers
• Exciton landscape in van der Waals heterostructures
• A scalable network model for electrically tunable ferroelectric domain structure in twistronic bilayers of two-dimensional semiconductors
• Extended magic phase in twisted graphene multilayers
• Moiré band structures of twisted phosphorene bilayers
• Impact of atomic reconstruction on optical spectra of twisted TMD homobilayers
• Direct visualization of hybrid excitons in van der Waals heterostructures
• Polarization and charge-separation of moiré excitons in van der Waals heterostructures
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• Considerations for extracting moiré-level strain from dark field intensities in transmission electron microscopy
• Strain-dependent one-dimensional confinement channels in twisted bilayer 1T${}^{\prime }$-WTe${}_2$
• Origin of Moiré Potentials in WS${}_2$/WSe${}_2$ Heterobilayers: Contributions from Lattice Reconstruction and Interlayer Charge Transfer