Double-Weyl phonons in transition-metal monosilicides

Abstract

Topological states of electrons and photons have attracted significant interest recently. Topological mechanical states also being actively explored, have been limited to macroscopic systems of kHz frequency. The discovery of topological phonons of atomic vibrations at THz frequency can provide a new venue for studying heat transfer, phonon scattering and electron-phonon interaction. Here, we employed ab initio calculations to identify a class of noncentrosymmetric materials of $M$Si ($M$=Fe,Co,Mn,Re,Ru) having double Weyl points in both their acoustic and optical phonon spectra. They exhibit novel topological points termed "spin-1 Weyl point" at the Brillouin zone~(BZ) center and "charge-2 Dirac point" at the zone corner. The corresponding gapless surface phonon dispersions are double helicoidal sheets whose isofrequency contours form a single non-contractible loop in the surface BZ. In addition, the global structure of the surface bands can be analytically expressed as double-periodic Weierstrass elliptic functions. Our prediction of topological bulk and surface phonons can be experimentally verified by neutron scattering and electron energy loss spectroscopy, opening brand new directions for topological phononics.

5 pages, 4 figures

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• Topological Photonics
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Cited by in corpus (25)

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• Angle-resolved photoemission spectroscopy and its application to topological materials
• Phononic Helical Nodal Lines with $\mathcal{P}\mathcal{T}$ Protection in MoB${}_2$
• Twofold quadruple Weyl nodes in chiral cubic crystals
• Ideal Unconventional Weyl Point in a Chiral Photonic Metamaterial
• Topological phonons in oxide perovskites controlled by light
• Quasiparticle Interference Evidence of the Topological Fermi Arc States in Chiral Fermionic Semimetal CoSi
• Chiral fermion reversal in chiral crystals
• Observation of multiple types of topological fermions in PdBiSe
• Charge-4 Weyl point: Minimum lattice model and chirality-dependent properties
• Weyl phonons in chiral crystals
• Single crystal growth and magnetoresistivity study of topological semimetal CoSi
• Chiral phonons in honeycomb sublattice of layered CoSn-like compounds
• Topological effects of phonons in GaN and AlxGa1-xN: A potential perspective for tuning phonon transport
• Weyl Phonons: The connection of topology and chirality
• Spin-1 Weyl Point and Surface Arc State in a Chiral Phononic Crystal
• Spin Waves and Dirac Magnons in a Honeycomb Lattice Zig-zag Antiferromagnet BaNi2(AsO4)2
• Strain-induced topological charge control in multifold fermion systems
• Topological band structure of surface acoustic waves on a periodically corrugated surface
• Predicting topological materials: symmetry-based indicator theories and beyond
• Chiral Topological Phononic Quasiparticles in Enantiomeric Crystals SrSi${}_2$ and BaSi${}_2$
• Topological excitations in quasi two-dimensional quantum magnets with weak interlayer interactions
• Extremely broadband topological surface states in a photonic topological metamaterials
• Discovery of ideal Weyl points with helicoid surface states
• Three-nodal surface phonons in solid-state materials: Theory and material realization