Topologically protected interface phonons in two-dimensional nanomaterials: hexagonal boron nitride and silicon carbide

Abstract

We perform both lattice dynamics analysis and molecular dynamics simulations to demonstrate the existence of topologically protected phonon modes in a two-dimensional, monolayer hexagonal boron nitride sheet. The topological phonon modes are found to be localized at an in-plane interface that divides the system into two regions of distinct valley Chern numbers. The dispersion of this topological phonon mode crosses over the frequency gap [1123, 1278] cm^{-1}, which is opened through analogy with the quantum valley Hall effect by breaking inversion symmetry of the boron and nitride atoms in the primitive unit cell. Consequently, vibrational energy with frequency within this gap is topologically protected, resulting in wave propagation that exhibits minimal backscattering, is robust with regards to structural defects such as sharp corners, and exhibits excellent temporal stability. Our findings open up the possibility of realizing topological phonons and mechanics in two-dimensional nanomaterials.

Nanoscale, accepted

References in corpus (17)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Topological Photonics
• Valley filter and valley valve in graphene
• Topological Acoustics
• Observation of phononic helical edge states in a mechanical 'topological insulator'
• Valley-contrasting orbital angular momentum in photonic valley crystals
• Topological modes bound to dislocations in mechanical metamaterials
• Topological Nature of the Phonon Hall Effect
• Edge waves in plates with resonators: An elastic analogue of the quantum valley Hall effect
• Classification of topological phonons in linear mechanical metamaterials
• Electronic Structures of SiC Nanoribbons
• Dislocations and Grain Boundaries in Two-Dimensional Boron Nitride
• Model for Topological Phononics and Phonon Diode
• Topological phonons and Weyl lines in 3 dimensions
• Dynamical Majorana Edge Modes in a Broad Class of Topological Mechanical Systems
• Topological phonon modes in filamentous structures
• Topological Phonon Modes in A Two-Dimensional Wigner Crystal

Cited by in corpus (10)

• Tutorial: Computing topological invariants in two-dimensional photonic crystals
• Theory and Experimental Investigation of the Quantum Valley Hall Effect
• Topological effects of phonons in GaN and AlxGa1-xN: A potential perspective for tuning phonon transport
• Double Dirac Cones and Topologically Non-Trivial Phonons for Continuous, Square Symmetric (C${}_{4v}$ and C${}_{2v}$) Unit Cells
• Strain Tunable Phononic Topological Bandgaps in Two-Dimensional Hexagonal Boron Nitride
• Valley-Chern Effect with LC-Resonators: A Modular Platform
• Symmetry-enforced planar nodal chain phonons in non-symmorphic materials
• Observation of Topological Nodal-Ring Phonons in Monolayer Hexagonal Boron Nitride
• Generation of phonon quantum states and quantum correlations among single photon emitters in hexagonal boron nitride
• Nonlocality and Strength of Interatomic Interactions Inducing the Topological Phonon Phase Transition