Cornertronics in Two-Dimensional Second-Order Topological Insulators

Abstract

Traditional electronic devices rely on the electron's intrinsic degrees of freedom (d.o.f.) to process information. However, additional d.o.f. like the valley, can emerge in the low-energy states of certain systems. Here, we show that the quantum dots (QDs) constructed from two-dimensional (2D) second-order topological insulators (SOTI) posses a new kind of d.o.f., namely corner freedom, related to the topological corner states that reside at different corners of the systems. Since the corner states are well separated in real space, they can be individually and intuitively manipulated, giving rise to the concept of cornertronics. Via symmetry analysis and material search, we identify the TiSiCO-family monolayers as the first prototype of cornertronics materials, where the corner states can be controlled by both electric and optical fields, due to novel corner-layer coupling (CLC) effect and corner-contrasted linear dichroism. Furthermore, we find that the band gap of the TiSiCO nanodisk lies in the terahertz region and is robust to size reduction. These results indicate that the TiSiCO nanodisks can be used to design terahertz devices with ultrasmall size and electric-field tunable band gap. Besides, the TiSiCO nanodisks are simultaneously sensitive to both the strength and polarization of the terahertz waves. Our findings not only pave the way for cornertronics, but also open a new direction for research in 2D SOTI, QD and terahertz electronics.

References in corpus (50)

• Spintronics: Fundamentals and applications
• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• WannierTools: An open-source software package for novel topological materials
• Antiferromagnetic spintronics
• Quantized Electric Multipole Insulators
• Valley filter and valley valve in graphene
• Higher-Order Topological Insulators
• Silicon Quantum Electronics
• $(d-2)$-dimensional edge states of rotation symmetry protected topological states
• Bismuthene on a SiC Substrate: A Candidate for a New High-Temperature Quantum Spin Hall Paradigm
• Reflection symmetric second-order topological insulators and superconductors
• Topological Band Engineering of Graphene Nanoribbons
• Concepts of Ferrovalley Material and Anomalous Valley Hall Effect
• Gate-tunable Topological Valley Transport in Bilayer Graphene
• Irvsp: to obtain irreducible representations of electronic states in the VASP
• Two-dimensional second-order topological insulator in graphdiyne
• Field-induced polarisation of Dirac valleys in bismuth
• Higher-Order Topological Insulator in Twisted Bilayer Graphene
• Band Topology and Linking Structure of Nodal Line Semimetals with Z2 Monopole Charges
• High-Temperature Majorana Corner States
• Generation of pure bulk valley current in graphene
• Engineering Corner States from Two-Dimensional Topological Insulators
• Two-dimensional higher-order topology in monolayer graphdiyne
• Universal Approach to Magnetic Second-Order Topological Insulator
• Graphene Nanobubbles as Valley Filters and Beamsplitters
• A valley valve and electron beam splitter
• $PT$ Symmetric Real Dirac Fermions and Semimetals
• Valley-Layer Coupling: A New Design Principle for Valleytronics
• Topological switch between second-order topological insulators and topological crystalline insulators
• Spin and Valley States in Gate-defined Bilayer Graphene Quantum Dots
• Magnetic second-order topological insulators and semimetals
• Spin-valley filtering in strained graphene structures with artificially induced carrier mass and spin-orbit coupling
• Topological and holonomic quantum computation based on second-order topological superconductors
• Current partition at topological zero-line intersections
• Braiding Majorana corner modes in a second-order topological superconductor
• Perfect Valley Filter in Topological Domain Wall
• Electron-hole crossover in gate-controlled bilayer graphene quantum dots
• $C_n$-symmetric higher-order topological crystalline insulators in atomically thin transition-metal dichalcogenides
• General corner charge formula in two-dimensional C_n-symmetric higher-order topological insulators
• Charge detection in gate-defined bilayer graphene quantum dots
• Second Order Topological Insulator State in Hexagonal Lattices and its Abundant Material Candidates
• Valley-polarized quantum anomalous Hall phase and disorder induced valley-filtered chiral edge channels
• Manipulation and Characterization of the Valley Polarized Topological Kink States in Graphene Based Interferometers
• Multi-orbital model reveals second-order topological insulator in 1H-transition metal dichalcogenide
• Phononic real Chern insulator with protected corner modes in graphynes
• Ferroelectric higher-order topological insulator in two dimensions
• Encyclopedia of emergent particles in 528 magnetic layer groups and 394 magnetic rod groups
• Second-Order Topological Insulator in van der Waals Heterostructures of CoBr${}_2$/Pt${}_2$HgSe${}_3$/CoBr${}_2$
• Second-Order Topological Insulator in Two-Dimensional C2N and Its Derivatives
• Quantized charge-pumping in higher-order topological insulators

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• Fractional corner charges in threefold-symmetric two-dimensional materials with fragile topology
• Two-dimensional orbital-obstructed insulators with higher-order band topology
• Second-order topological insulator induced by compensated altermagnetism without bulk spin splitting