Flat and tunable moire phonons in twisted transition-metal dichalcogenides
arXiv:2406.18779 · doi:10.1103/PhysRevLett.134.026501
Abstract
Displacement fields are one of the main tuning knobs employed to engineer flat electronic band dispersions in twisted van der Waals multilayers. Here, we show that electric fields can also be used to tune the phonon dispersion of moiré superlattices formed by non-centrosymmetric materials, focusing on twisted transition metal dichalcogenide homobilayers. This effect arises from the intertwining between the local stacking configuration and the formation of polar domains within the moiré supercell. For small twist angles, increasing the electric field leads to a universal moiré phonon spectrum characterized by a substantially softened longitudinal acoustic phason mode and a flat optical phonon mode, both of which cause a significant enhancement in the vibrational density of states. The phasons also acquire a prominent chiral character, displaying a nonzero angular momentum spread across the Brillouin zone. We discuss how the tunability of the moiré phonon spectra may affect electronic properties, focusing on the recently discovered phenomenon of van der Waals ferroelectricity.
6 pages + SM; comments are welcome
References in corpus (34)
- Magic-angle graphene superlattices: a new platform for unconventional superconductivity
- Moire bands in twisted double-layer graphene
- Superconductors, Orbital Magnets, and Correlated States in Magic Angle Bilayer Graphene
- Stacking-engineered ferroelectricity in bilayer boron nitride
- Tunable Phase Boundaries and Ultra-Strong Coupling Superconductivity in Mirror Symmetric Magic-Angle Trilayer Graphene
- Interfacial Ferroelectricity by van-der-Waals Sliding
- Signatures of Gate-Tunable Superconductivity in Trilayer Graphene/Boron Nitride Moiré Superlattice
- Twistable electronics with dynamically rotatable heterostructures
- Lattice relaxation and energy band modulation in twisted bilayer graphenes
- Interfacial ferroelectricity in rhombohedral-stacked bilayer transition metal dichalcogenides
- Twistronics: Manipulating the Electronic Properties of Two-dimensional Layered Structures through their Twist Angle
- Strongly Correlated Chern Insulators in Magic-Angle Twisted Bilayer Graphene
- Valley contrasting chiral phonons in monolayer hexagonal lattices
- Novel effects of strains in graphene and other two dimensional materials
- Interfacial ferroelectricity in marginally twisted 2D semiconductors
- Chern Insulators and Topological Flat-bands in Magic-angle Twisted Bilayer Graphene
- Helicity resolved Raman scattering of MoS2, MoSe2, WS2 and WSe2 atomic layers
- Relaxation and Domain Formation in Incommensurate 2D Heterostructures
- The Quantum Twisting Microscope
- Moiré phonons in the twisted bilayer graphene
- Continuum model for relaxed twisted bilayer graphenes and moiré electron-phonon interaction
- Polar meron-antimeron networks in strained and twisted bilayers
- Phonons in Twisted Transition Metal Dichalcogenide Bilayers ("Twistnonics"): Ultra-soft Phasons, and a transition from Superlubric to Pinned Phase
- Moiré-pattern fluctuations and electron-phason coupling in twisted bilayer graphene
- The sliding phase transition in ferroelectric van der Waals bilayers
- Phonons in magic-angle twisted bilayer graphene
- Weyl phonons in chiral crystals
- A scalable network model for electrically tunable ferroelectric domain structure in twistronic bilayers of two-dimensional semiconductors
- Symmetry Origin of Lattice Vibration Modes in Twisted Multilayer Graphene: Phasons vs Moiré Phonons
- Low-energy moiré phonons in twisted bilayer van der Waals heterostructures
- Theory of polarization textures in crystal supercells
- Moiré phonons in graphene/hexagonal boron nitride moiré superlattice
- Moiré phonons and impact of electronic symmetry breaking in twisted trilayer graphene
- Extended linear-in- resistivity due to electron-phason scattering in moiré superlattices