Spin-filtered edge states with an electrically tunable gap in a two-dimensional topological crystalline insulator

Abstract Magnetic topological states have attracted significant attentions due to their intriguing quantum phenomena and potential applications in topological spintronic devices. Here, we propose a two-dimensional material NpAs monolayer as a candidate for multiple topological states accompanied with the changes of magnetic structures. Under the antiferromagnetic configuration, the long-awaited topological crystalline insulator (TCI) emerges with a nonzero mirror Chern number $\mathcal{C_M} = 1$ and a giant band gap of 630 meV, and remarkably a pair of gapless edge states can be tailored by rotating the magnetization directions while the TCI phase survives. Moreover, we establish the existence of quantum anomalous Hall effect and nontrivial nodal points under the ferromagnetic configuration, thereby giving rise to the mixed Weyl semimetal after adding the magnetization direction to topological classification. Our findings not only provide an ideal candidate for uncovering exotic topological characters with magnetism but also put forward potential applications in topological spintronics.

Download Full-text

Theoretical realization of two-dimensional Dirac/Weyl line-node and traversing edge states in penta-X2Y monolayers

Applied Materials Today ◽

10.1016/j.apmt.2021.101057 ◽

2021 ◽

Vol 23 ◽

pp. 101057

Author(s):

Lirong Wang ◽

Lei Jin ◽

Guodong Liu ◽

Ying Liu ◽

Xuefang Dai ◽

...

Keyword(s):

Two Dimensional ◽

Edge States ◽

Line Node

Download Full-text

Schwarzian quantum mechanics as a Drinfeld-Sokolov reduction of BF theory

Journal of High Energy Physics ◽

10.1007/jhep12(2020)189 ◽

2020 ◽

Vol 2020 (12) ◽

Author(s):

Fridrich Valach ◽

Donald R. Youmans

Keyword(s):

Quantum Mechanics ◽

Partition Function ◽

Gauge Group ◽

Path Integral ◽

Coadjoint Orbits ◽

Two Dimensional ◽

Edge States ◽

Class Constraint ◽

Action Functional ◽

Bf Theory

Abstract We give an interpretation of the holographic correspondence between two-dimensional BF theory on the punctured disk with gauge group PSL(2, ℝ) and Schwarzian quantum mechanics in terms of a Drinfeld-Sokolov reduction. The latter, in turn, is equivalent to the presence of certain edge states imposing a first class constraint on the model. The constrained path integral localizes over exceptional Virasoro coadjoint orbits. The reduced theory is governed by the Schwarzian action functional generating a Hamiltonian S1-action on the orbits. The partition function is given by a sum over topological sectors (corresponding to the exceptional orbits), each of which is computed by a formal Duistermaat-Heckman integral.

Download Full-text

Systematic Investigation of the Coupling between One-Dimensional Edge States of a Topological Crystalline Insulator

Physical Review Letters ◽

10.1103/physrevlett.126.236402 ◽

2021 ◽

Vol 126 (23) ◽

Author(s):

Johannes Jung ◽

Artem Odobesko ◽

Robin Boshuis ◽

Andrzej Szczerbakow ◽

Tomasz Story ◽

...

Keyword(s):

Systematic Investigation ◽

Edge States ◽

One Dimensional ◽

Topological Crystalline Insulator

Download Full-text

Edge states in a two-dimensional honeycomb lattice of massive magnetic skyrmions

Physical Review B ◽

10.1103/physrevb.98.180407 ◽

2018 ◽

Vol 98 (18) ◽

Cited By ~ 14

Author(s):

Z.-X. Li ◽

C. Wang ◽

Yunshan Cao ◽

Peng Yan

Keyword(s):

Honeycomb Lattice ◽

Two Dimensional ◽

Edge States ◽

Magnetic Skyrmions

Download Full-text

Dual-mode of topological rainbow in gradual photonic heterostructures

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac37df ◽

2021 ◽

Author(s):

Mingxing Li ◽

Yueke Wang ◽

Mengjia Lu ◽

Tian Sang

Keyword(s):

Finite Element Method ◽

Finite Element Method Simulation ◽

Two Dimensional ◽

Edge States ◽

Dual Mode ◽

Strong Robustness ◽

Mode Excitation ◽

Simulation Results ◽

Photonic States ◽

Sandwiched Structure

Abstract In this letter, a method to realize the topological rainbow trapping is presented, which is composed of gradual ordinary-topological-ordinary heterostructures based on two-dimensional photonic crystals with C-4 symmetry. In the proposed sandwiched structure, the two coupled topological edge states with different frequencies are separated and trapped in different positions, due to group velocity of near to zero. We have achieved the dual-mode of topological rainbow in one structure, which broadens the bandwidth. Besides, the dual-mode of topological rainbow under one mode excitation is also realized by using a simple bend design. The immunity to defects is also investigated and it is found our slowing light system has strong robustness. Finite Element Method simulation results verify our idea, and our work opens up a new way for frequency routing and broadband operation of topological photonic states.

Download Full-text