Coexistence of open and closed type nodal line topological semimetals in two dimensional B2C

2018 ◽  
Vol 6 (5) ◽  
pp. 1206-1214 ◽  
Author(s):  
P. Zhou ◽  
Z. S. Ma ◽  
L. Z. Sun
Keyword(s):  
Nodal Line ◽  
Two Dimensional ◽  
Nodal Lines ◽  
Closed Type ◽  
Topological Semimetal ◽  
Topological Semimetals

The detection of open and closed type nodal lines in the bilayer topological semimetal B2C on the substrate of Cu(110).

Electronic Structure Transformation in a Magnetized Topological Semimetal

2021 ◽  
Vol 1 ◽  
Keyword(s):  
Electronic Structure ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Localized States ◽  
Structure Transformation ◽  
Nodal Lines ◽  
Topological Semimetal ◽  
Magnetic Domain Walls ◽  
Magnetic Orders ◽  
Topological Semimetals

We theoretically show that the nodal structures in topological semimetals, including Weyl points and nodal lines, can be switched by magnetic orders, accompanied by localized states at magnetic domain walls.

scholarly journals Transport of Topological Semimetals

2019 ◽  
Vol 49 (1) ◽  
pp. 207-252 ◽  
Author(s):  
Jin Hu ◽  
Su-Yang Xu ◽  
Ni Ni ◽  
Zhiqiang Mao
Keyword(s):  
Transport Properties ◽  
Structural Characteristics ◽  
Nodal Point ◽  
Experimental Studies ◽  
Anomalous Hall Effect ◽  
Nodal Line ◽  
Chiral Anomaly ◽  
Energy Excitation ◽  
Topological Semimetal ◽  
Topological Semimetals

Three-dimensional (3D) topological semimetals represent a new class of topological matters. The study of this family of materials has been at the frontiers of condensed matter physics, and many breakthroughs have been made. Several topological semimetal phases, including Dirac semimetals (DSMs), Weyl semimetals (WSMs), nodal-line semimetals (NLSMs), and triple-point semimetals, have been theoretically predicted and experimentally demonstrated. The low-energy excitation around the Dirac/Weyl nodal points, nodal line, or triply degenerated nodal point can be viewed as emergent relativistic fermions. Experimental studies have shown that relativistic fermions can result in a rich variety of exotic transport properties, e.g., extremely large magnetoresistance, the chiral anomaly, and the intrinsic anomalous Hall effect. In this review, we first briefly introduce band structural characteristics of each topological semimetal phase, then review the current studies on quantum oscillations and exotic transport properties of various topological semimetals, and finally provide a perspective of this area.

A Simple Technique for Maximizing the Fundamental Frequency of Vibrating Structures

2000 ◽  
Vol 122 (4) ◽  
pp. 341-349 ◽  
Author(s):  
J. H. Ong ◽  
G. H. Lim
Keyword(s):  
Natural Frequency ◽  
Dimensional Analysis ◽  
Simple Technique ◽  
Nodal Line ◽  
The Other ◽  
Two Dimensional ◽  
Nodal Lines ◽  
Vibrating Structures ◽  
Original Configuration ◽  
The Ideal

A general approach for finding the optimal support locations to maximize the fundamental natural frequency of vibrating structures is described in this paper. The key to the procedure is to place the necessary supports in such a way, so as to eliminate the lower modes from the original configuration. This is accomplished by placing supports along the nodal lines of the highest possible mode from the original configuration, so that all the other lower modes are eliminated by the introduction of new or extra supports to the structure. For two-dimensional analysis, the average driving point residues calculated along a nodal line is used as an indicator for finding the vicinity of the ideal support locations. [S1043-7398(00)00504-1]

scholarly journals Glide symmetry protected higher-order topological insulators from semimetals with butterfly-like nodal lines

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiaoting Zhou ◽  
Chuang-Han Hsu ◽  
Cheng-Yi Huang ◽  
Mikel Iraola ◽  
Juan L. Mañes ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Topological Insulators ◽  
Surface States ◽  
Nodal Line ◽  
Higher Order ◽  
Dirac Fermion ◽  
Space Groups ◽  
Nodal Lines ◽  
Topological Semimetals ◽  
Symmetry Protected

AbstractMost topological insulators (TIs) discovered today in spinful systems can be transformed from topological semimetals (TSMs) with vanishing bulk gap via introducing the spin-orbit coupling (SOC), which manifests the intrinsic links between the gapped topological insulator phases and the gapless TSMs. Recently, we have discovered a family of TSMs in time-reversal invariant spinless systems, which host butterfly-like nodal-lines (NLs) consisting of a pair of identical concentric intersecting coplanar ellipses (CICE). In this Communication, we unveil the intrinsic link between this exotic class of nodal-line semimetals (NLSMs) and a $${{\mathbb{Z}}}_{4}$$ Z 4 = 2 topological crystalline insulator (TCI), by including substantial SOC. We demonstrate that in three space groups (i.e., Pbam (No.55), P4/mbm (No.127), and P42/mbc (No.135)), the TCI supports a fourfold Dirac fermion on the (001) surface protected by two glide symmetries, which originates from the intertwined drumhead surface states of the CICE NLs. The higher order topology is further demonstrated by the emergence of one-dimensional helical hinge states, indicating the discovery of a higher order topological insulator protected by a glide symmetry.

scholarly journals Topological semimetal in honeycomb lattice LnSI

2017 ◽  
Vol 114 (40) ◽  
pp. 10596-10600 ◽  
Author(s):  
Simin Nie ◽  
Gang Xu ◽  
Fritz B. Prinz ◽  
Shou-cheng Zhang
Keyword(s):  
Condensed Matter ◽  
Surface States ◽  
Nodal Line ◽  
Honeycomb Lattice ◽  
Nodal Lines ◽  
Weyl Semimetal ◽  
The Standard Model ◽  
Weyl Semimetals ◽  
Topological Semimetals ◽  
The Right

Recognized as elementary particles in the standard model, Weyl fermions in condensed matter have received growing attention. However, most of the previously reported Weyl semimetals exhibit rather complicated electronic structures that, in turn, may have raised questions regarding the underlying physics. Here, we report promising topological phases that can be realized in specific honeycomb lattices, including ideal Weyl semimetal structures, 3D strong topological insulators, and nodal-line semimetal configurations. In particular, we highlight a semimetal featuring both Weyl nodes and nodal lines. Guided by this model, we showed that GdSI, the long-perceived ideal Weyl semimetal, has two pairs of Weyl nodes residing at the Fermi level and that LuSI (YSI) is a 3D strong topological insulator with the right-handed helical surface states. Our work provides a mechanism to study topological semimetals and proposes a platform for exploring the physics of Weyl semimetals as well as related device designs.

scholarly journals Double-bowl state in photonic Dirac nodal line semimetal

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Mengying Hu ◽  
Ye Zhang ◽  
Xi Jiang ◽  
Tong Qiao ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Surface States ◽  
Nodal Line ◽  
Electronic Systems ◽  
Nodal Lines ◽  
Spectrum Range ◽  
The Past ◽  
Topological Materials ◽  
Classical Waves ◽  
Topological Semimetals ◽  
Polarized Surface

AbstractThe past decade has seen a proliferation of topological materials for both insulators and semimetals in electronic systems and classical waves. Topological semimetals exhibit topologically protected band degeneracies, such as nodal points and nodal lines. Dirac nodal line semimetals (DNLS), which own four-fold line degeneracy, have drawn particular attention. DNLSs have been studied in electronic systems but there is no photonic DNLS. Here in this work, we provide a new mechanism, which is unique for photonic systems to investigate a stringent photonic DNLS. When truncated, the photonic DNLS exhibits double-bowl states (DBS), which comprise two sets of perpendicularly polarized surface states. In sharp contrast to nondegenerate surface states in other photonic systems, here the two sets of surface states are almost degenerate over the whole-spectrum range. The DBS and the bulk Dirac nodal ring (DNR) dispersion along the relevant directions, are experimentally resolved.

Strain tuning of closed topological nodal lines and opposite pockets in quasi-two-dimensional α-phase FeSi2

2020 ◽  
Vol 22 (24) ◽  
pp. 13650-13658 ◽  
Author(s):  
Xiaotian Wang ◽  
Zhenxiang Cheng ◽  
Gang Zhang ◽  
Minquan Kuang ◽  
Xiao-Lin Wang ◽  
...  
Keyword(s):  
Mechanical Strain ◽  
Nodal Line ◽  
Type I ◽  
Type Ii ◽  
Two Dimensional ◽  
Nodal Lines ◽  
Hybrid Type ◽  
Α Phase ◽  
Single Material

α-FeSi2 is a valuable candidate for spintronics application by utilization of type I, type II, and hybrid-type topological nodal line semimetals in a single material tuned by mechanical strain.

scholarly journals An improved holographic nodal line semimetal

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Yan Liu ◽  
Xin-Meng Wu
Keyword(s):  
Mass Term ◽  
Nodal Line ◽  
Duality Relation ◽  
Strongly Coupled ◽  
Nodal Lines ◽  
Form Field ◽  
Improved Model ◽  
Fermionic Spectrum ◽  
Chern Simons ◽  
Tensor Operators

Abstract We study an improved holographic model for the strongly coupled nodal line semimetal which satisfies the duality relation between the rank two tensor operators $$ \overline{\psi}{\gamma}^{\mu v}\psi $$ ψ ¯ γ μv ψ and $$ \overline{\psi}{\gamma}^{\mu v}{\gamma}^5\psi $$ ψ ¯ γ μv γ 5 ψ . We introduce a Chern-Simons term and a mass term in the bulk for a complex two form field which is dual to the above tensor operators and the duality relation is automatically satisfied from holography. We find that there exists a quantum phase transition from a topological nodal line semimetal phase to a trivial phase. In the topological phase, there exist multiple nodal lines in the fermionic spectrum which are topologically nontrivial. The bulk geometries are different from the previous model without the duality constraint, while the resulting properties are qualitatively similar to those in that model. This improved model provides a more natural ground to analyze transports or other properties of strongly coupled nodal line semimetals.

scholarly journals Two-dimensional Weyl points and nodal lines in pentagonal materials and their optical response

Nanoscale ◽  
2021 ◽  
Author(s):  
Sergio Bravo ◽  
M. Pacheco ◽  
V. Nuñez ◽  
J. D. Correa ◽  
Leonor Chico
Keyword(s):  
First Principles ◽  
Optical Response ◽  
Symmetry Analysis ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Nodal Lines

A symmetry analysis combined with first-principles calculations of two-dimensional pentagonal materials (PdSeTe, PdSeS, InP5 and GeBi2) based on the Cairo tiling reveal nontrivial spin textures, nodal lines and Weyl points.

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