Physics of Phonons in Systems with Approximate Screw Symmetry
arXiv:2206.06633 · doi:10.1103/PhysRevB.106.184104
Abstract
Properties of systems with exact n-fold screw symmetry (n=2, 3, 4, 6) have been well studied because they can be understood in terms of space groups. On the other hand, existence of materials with approximate screw symmetries, such as 7-fold and 10-fold screw symmetries, has been predicted. In this paper, we study properties of phonons in crystals with approximate screw symmetries, which will lead to unique and new physical phenomena. In a crystal with an approximate screw symmetry, we propose a method to extract information of pseudoangular momentum of phonons, which is a quantum number characterizing the properties of phonon modes under screw symmetry, based on the fact that the information of the quantum numbers defined under exact screw symmetry partially remains in the eigenvectors of approximate screw symmetric systems. As a preparation, we study a one-dimensional crystal with partially broken translation symmetry to have an enlarged unit cell, and we show how to extract information of a quantum number corresponding to the pseudoangular momentum, by studying a relative phase between neighboring atoms. We also extend this method to systems with an approximate screw symmetry, and discuss properties of the pseudoangular momentum. We apply this method to results of our first-principle calculations on candidate materials with an approximate translational symmetry or with an approximate screw symmetry, and show how this approximate symmetry is reflected in the phonon wavefunctions.
arXiv comment16 pages, 11 figures, to be published in Phys. Rev. B
References in corpus (18)
- Valley contrasting chiral phonons in monolayer hexagonal lattices
- Double-Weyl phonons in transition-metal monosilicides
- Phonons become chiral in the pseudogap phase of cuprates
- Truly chiral phonons in α-HgS
- Emerging Photoluminescence from the Dark-Exciton Phonon Replica in Monolayer WSe2
- Pseudospins and topological effects of phonons in a Kekule lattice
- Entanglement of single-photons and chiral phonons in atomically thin WSe
- Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon
- Valley-selective chiral phonon replicas of dark excitons and trions in monolayer WSe2
- Chiral Phonons in Chiral Materials
- Chirality-induced Phonon Dispersion in a Noncentrosymmetric Micropolar Crystal
- Chiral phonons and pseudo-angular momentum in non-symmorphic systems
- Chiral Phonons in Moiré Superlattices
- Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP
- Flipping exciton angular momentum with chiral phonons in MoSe/WSe heterobilayers
- Chiral valley phonons and flat phonon bands in moiré materials
- Observation of a Chiral Wave Function in Twofold Degenerate Quadruple Weyl System BaPtGe
- Chiral phonons entangled with multiple Hall effects and unified convention for pseudoangular momentum in 2D materials