Manipulating the one-dimensional topological edge state of Bi bilayer nanoribbons via magnetic orientation and electric field

Abstract

Despite the superiority of two-dimensional (2D) topological insulators (TIs) over their three-dimensional (3D) counterparts in various aspects and the essential distinction between them in structural symmetry, the variation of the topological 1D edge states upon magnetic interaction and their application for spintronic devices have not been sufficiently illuminated. Here, we reveal that 1D edge states of 2D TI have a unique magnetic response never observed in 2D surface states of 3D TI, and using this exotic nature we propose a new way to utilize the spin-polarized channel for spintronic applications. We investigate the effects of width and magnetic decoration on the 1D topological edge state of Bi-bilayer nanoribbons (BNRs). Through the Zak phase, we find that the zero-energy states are enforced at the magnetic domain boundaries in the Cr-decorated BNR and directly examine their robustness using short-range magnetic domain structures. We also demonstrate that 1D edge states of BNRs can be selectively and reversibly controlled by the combination of magnetic reorientation and electric field without compromising their structural integrity. Our work provides a fundamental understanding of 1D topological edge states, and shows the opportunity of using these features in spintronic devices.

Long range dynamical coupling between magnetic adatoms mediated by a 2D topological insulator

“…From the fundamental point of view, it is intriguing to enquire about the strength and nature of the coupling between magnetic units and the topologically protected edge states. From the technological side, functionalization with magnetic adatoms may be an efficient route to tap into the attractive properties of TPES [9,10]. As an added bonus, the high spinorbit coupling strength necessary to produce topologically non-trivial states may also endow magnetic adatoms with magnetocrystalline anisotropy large enough to stabilize the magnetization direction against quantum and thermal fluctuations.…”

Band Structure and Quantum Conductance of Surface-unsaturated and Hydrogenated Sb and Bi Monolayer Nanoribbons

“…[1][2][3][4] Nanostructured 2D materials, such as h-BN, MoS 2 and Bi-bilayer, with controllable edge-states in atomic scales enable their electronic devices to be integrated in high compact and stability, and more sensitive to accurate controls. [5][6][7] For the one-dimensional (1D) nanoribbon or nanowires of these 2D materials, the magnetic domain boundaries can be controlled accurately due to magnetic anisotropy in dismiss of atomic neighbors, accounting for their topological, magnetic and electron-transport properties that highly sensitive to lattice strain, magnetic order, and voltage bias. The edge states of 2D TIs is essentially different to the surface states of 3D TIs, and thus the effective description of 1D topological edge-states should be intensively renovated.…”