$C_n$-symmetric higher-order topological crystalline insulators in atomically thin transition-metal dichalcogenides

Abstract

Based on first-principles calculations and symmetry analysis, we predict atomically thin ($1-N$ layers) 2H group-VIB TMDs $M{X}_2$ ($M$ = Mo, W; $X$ = S, Se, Te) are large-gap higher-order topological crystalline insulators protected by $C_3$ rotation symmetry. We explicitly demonstrate the nontrivial topological indices and existence of the hallmark corner states with quantized fractional charge for these familiar TMDs with large bulk optical band gaps ($1.64-1.95$ eV for the monolayers), which would facilitate the experimental detection by STM. We find that the well-defined corner states exist in the triangular finite-size flakes with armchair edges of the atomically thin ($1-N$ layers) 2H group-VIB TMDs, and the corresponding quantized fractional charge is the number of layers $N$ divided by 3 modulo integers, which will simply double including spin degree of freedom.

References in corpus (9)

• Electric Multipole Moments, Topological Multipole Moment Pumping, and Chiral Hinge States in Crystalline Insulators
• $(d-2)$-dimensional edge states of rotation symmetry protected topological states
• Reflection symmetric second-order topological insulators and superconductors
• Higher-order topological insulators and semimetals on the breathing Kagome and pyrochlore lattices
• Higher-order Topology of Axion Insulator EuIn${}_2$As${}_2$
• Low-threshold topological nanolasers based on second-order corner state
• Surface State Magnetization and Chiral Edge States on Topological Insulators
• Second Order Topological Insulator State in Hexagonal Lattices and its Abundant Material Candidates
• Multi-orbital model reveals second-order topological insulator in 1H-transition metal dichalcogenide

Cited by in corpus (25)

• Creation and Manipulation of Higher-Order Topological States by Altermagnets
• Connecting Higher-Order Topology with the Orbital Hall Effect in Monolayers of Transition Metal Dichalcogenides
• Higher-order topological phases in crystalline and non-crystalline systems: a review
• Cornertronics in Two-Dimensional Second-Order Topological Insulators
• Orbital magnetoelectric effect in nanoribbons of transition metal dichalcogenides
• Second-order topological corner states in zigzag graphene nanoflake with different types of edge magnetic configurations
• Orbitronics in Two-dimensional Materials
• Engineering topologically protected zero-dimensional interface end states in antiferromagnetic heterojunction graphene nanoflakes
• High-Order Topological Phase Diagram Revealed by Anomalous Nernst Effect in Janus ScClI Monolayer
• Mirror real Chern insulator in two and three dimensions
• Abundance of second order topology in $C_3$ symmetric two-dimensional insulators
• Controlling the orbital Hall effect in gapped bilayer graphene in the terahertz regime
• Effect of local Coulomb interaction on Majorana corner modes: weak and strong correlation limits
• Spin-Selective Second-Order Topological Insulators Enabling Cornertronics in 2D Altermagnets
• Fractional corner charges in threefold-symmetric two-dimensional materials with fragile topology
• Ferroelectric polarization controlled orbital Hall conductivity in a higher-order topological insulator: \textit{d1T}-phase monolayer MoS${}_2$
• Two-dimensional orbital-obstructed insulators with higher-order band topology
• Orbital Hall effect and topology on a two-dimensional triangular lattice: from bulk to edge
• Recipe for higher-order topology on the triangular lattice
• Two-atom-thin topological crystalline insulators lacking out of plane inversion symmetry
• Evidence of phase stability, topological phonon and temperature-induced topological phase transition in rocksalt SnS and SnSe
• Second-order topological insulator in Bilayer borophene
• Floquet topological phases with time-reversal and space inversion symmetries and dynamical detection of topological charges
• Extrinsic higher-order topological corner states in AB-stacked transition-metal dichalcogenides
• Tunable corner states in topological insulators with long-range hoppings and diverse shapes