Triplon band splitting and topologically protected edge states in the dimerized antiferromagnet

Abstract

The search for topological insulators has been actively promoted in the field of condensed matter physics for further development in energy-efficient information transmission and processing. In this context, recent studies have revealed that not only electrons but also bosonic particles such as magnons can construct edge states carrying nontrivial topological invariants. Here we demonstrate topological triplon bands in the spin-1/2 two-dimensional dimerized quantum antiferromagnet Ba${}_2$CuSi${}_2$O${}_6$Cl${}_2$, which is closely related to a pseudo-one-dimensional variant of the Su-Schrieffer-Heeger (SSH) model, through inelastic neutron scattering experiments. The excitation spectrum exhibits two triplon bands and a clear band gap between them due to a small alternation in interdimer exchange interactions along the $a$-direction, which is consistent with the crystal structure. The presence of topologically protected edge states is indicated by a bipartite nature of the lattice.

arXiv comment15 pages, 8 figures

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Cited by in corpus (16)

• Topological Magnons: A Review
• Topological magnon insulator spin excitations in the two-dimensional ferromagnet CrBr${}_3$
• Topological phases of a dimerized Fermi-Hubbard model for semiconductor nano-lattices
• Non-Hermiticity and topological invariants of magnon Bogoliubov-de Gennes systems
• Observation of competing, correlated ground states in the flat band of rhombohedral graphite
• Topological magnetic excitations
• Evidence for magnon-phonon coupling in the topological magnet Cu${}_3$TeO${}_6$
• Dirac surface states in magnonic analogs of topological crystalline insulators
• Dirac cones and mass terms in bosonic spectra
• Dirac Hamiltonians for bosonic spectra
• Real-space imaging of dispersive triplon excitations in engineered quantum magnets
• Fragility of ${\mathcal{Z}}_2$ topological invariant characterizing triplet excitations in a bilayer kagome magnet
• Kitaev-Heisenberg model on the star lattice: From chiral Majorana fermions to chiral triplons
• Higher-order topology and corner triplon excitations in two-dimensional quantum spin-dimer models
• Evidence for strong correlations at finite temperatures in the dimerized magnet Na${}_2$Cu${}_2$TeO${}_6$
• Critical Berezinskii-Kosterlitz-Thouless dynamics in the archetypal two-dimensional spin system Ba${}_2$CuSi${}_2$O${}_6$Cl${}_2$