Chiral Topological Phononic Quasiparticles in Enantiomeric Crystals SrSi${}_2$ and BaSi${}_2$

Abstract

Chiral crystals have recently garnered significant interest in condensed matter physics due to their unique electronic and optical properties. In this paper, we explore the connection between the chirality of crystal structures and the chirality of topological quasiparticles. We specifically predict and analyze several chiral enantiomeric materials, such as SrSi${}_2$ and BaSi${}_2$, which crystallize in the chiral space groups $P4{}_{3}32$ and $P4{}_{1}32$. Based on first-principles calculations and theoretical analysis, we reveal that the phonon spectra of these materials host various topological phononic quasiparticles, including charge-2 triple points, charge-2 Dirac points, charge-2 Weyl points, and charge-1 Weyl points. Our paper shows that in these enantiomeric materials, the opposite chirality of the crystal structure results in topological quasiparticles with opposite chiral topological charges and distinct topological surface states. Our paper elucidates the intrinsic relationship between the chirality of crystal structures and the chirality of topological quasiparticles, providing promising theoretical guidance and material platform for investigating the physical properties of chiral crystals.

8 pages, 4 figures

References in corpus (14)

• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• Topological Node-Line Semimetal in Three Dimensional Graphene Networks
• Multiple types of topological fermions in transition metal silicides
• Large Fermi Arcs in Unconventional Weyl Semimetal RhSi
• Discovery of topological chiral crystals with helicoid arc states
• Double-Weyl phonons in transition-metal monosilicides
• Topological Nature of the Phonon Hall Effect
• Line of Dirac Nodes in Hyper-Honeycomb Lattices
• Nonsymmorphic-symmetry-protected hourglass Dirac loop, nodal line, and Dirac point in bulk and monolayer $X_3$SiTe${}_6$ ($X=$ Ta, Nb)
• Pseudospins and topological effects of phonons in a Kekule lattice
• Current-induced Orbital and Spin Magnetizations in Crystals with Helical Structure
• Phononic Helical Nodal Lines with $\mathcal{P}\mathcal{T}$ Protection in MoB${}_2$
• Chiral fermion reversal in chiral crystals
• Weyl phonons in chiral crystals