Phononic real Chern insulator with protected corner modes in graphynes

Abstract

Higher-order topological insulators have attracted great research interest recently. Different from conventional topological insulators, higher-order topological insulators do not necessarily require spin-orbit coupling, which makes it possible to realize them in spinless systems. Here, we study phonons in 2D graphyne family materials. By using first-principle calculations and topology/symmetry analysis, we find that phonons in both graphdiyne and $\gamma$-graphyne exhibit a second-order topology, which belongs to the specific case known as real Chern insulator. We identify the nontrivial phononic band gaps, which are characterized by nontrivial real Chern numbers enabled by the spacetime inversion symmetry. The protected phonon corner modes are verified by the calculation on a finite-size nanodisk. Our study extends the scope of higher-order topology to phonons in real materials. The spatially localized phonon modes could be useful for novel phononic applications.

6 pages, 5figures

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Cited by in corpus (7)

• Higher-order topological phases in crystalline and non-crystalline systems: a review
• Symmetry-Enforced Nodal Chain Phonons
• Cornertronics in Two-Dimensional Second-Order Topological Insulators
• Phononic Stiefel-Whitney topology with corner vibrational modes in two-dimensional Xenes and ligand-functionalized derivatives
• Mirror real Chern insulator in two and three dimensions
• Interlayer Coupling Induced Topological Phase Transition to Higher Order
• Second-order topological insulator induced by compensated altermagnetism without bulk spin splitting