Nodal Lines

Author(s):  
Krzysztof Burdzy
Keyword(s):  
2019 ◽  
Vol 3 (6) ◽  
Author(s):  
J. N. Nelson ◽  
J. P. Ruf ◽  
Y. Lee ◽  
C. Zeledon ◽  
J. K. Kawasaki ◽  
...  

2020 ◽  
Vol 102 (20) ◽  
Author(s):  
Susumu Minami ◽  
Fumiyuki Ishii ◽  
Motoaki Hirayama ◽  
Takuya Nomoto ◽  
Takashi Koretsune ◽  
...  

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Wei Luo ◽  
Yuma Nakamura ◽  
Jinseon Park ◽  
Mina Yoon

AbstractRecent experiments identified Co3Sn2S2 as the first magnetic Weyl semimetal (MWSM). Using first-principles calculation with a global optimization approach, we explore the structural stabilities and topological electronic properties of cobalt (Co)-based shandite and alloys, Co3MM’X2 (M/M’ = Ge, Sn, Pb, X = S, Se, Te), and identify stable structures with different Weyl phases. Using a tight-binding model, for the first time, we reveal that the physical origin of the nodal lines of a Co-based shandite structure is the interlayer coupling between Co atoms in different Kagome layers, while the number of Weyl points and their types are mainly governed by the interaction between Co and the metal atoms, Sn, Ge, and Pb. The Co3SnPbS2 alloy exhibits two distinguished topological phases, depending on the relative positions of the Sn and Pb atoms: a three-dimensional quantum anomalous Hall metal, and a MWSM phase with anomalous Hall conductivity (~1290 Ω−1 cm−1) that is larger than that of Co2Sn2S2. Our work reveals the physical mechanism of the origination of Weyl fermions in Co-based shandite structures and proposes topological quantum states with high thermal stability.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Yan Liu ◽  
Xin-Meng Wu

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.


Nanoscale ◽  
2021 ◽  
Author(s):  
Sergio Bravo ◽  
M. Pacheco ◽  
V. Nuñez ◽  
J. D. Correa ◽  
Leonor Chico

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.


2021 ◽  
Vol 103 (24) ◽  
Author(s):  
Jian Yang ◽  
Chen Fang ◽  
Zheng-Xin Liu

2021 ◽  
Vol 7 (13) ◽  
pp. eabf1467
Author(s):  
T. Asaba ◽  
V. Ivanov ◽  
S. M. Thomas ◽  
S. Y. Savrasov ◽  
J. D. Thompson ◽  
...  

The transverse voltage generated by a temperature gradient in a perpendicularly applied magnetic field, termed the Nernst effect, has promise for thermoelectric applications and for probing electronic structure. In magnetic materials, an anomalous Nernst effect (ANE) is possible in a zero magnetic field. We report a colossal ANE in the ferromagnetic metal UCo0.8Ru0.2Al, reaching 23 microvolts per kelvin. Uranium’s 5f electrons provide strong electronic correlations that lead to narrow bands, a known route to producing a large thermoelectric response. In addition, uranium’s strong spin-orbit coupling produces an intrinsic transverse response in this material due to the Berry curvature associated with the relativistic electronic structure. Theoretical calculations show that in UCo0.8Ru0.2Al at least 148 Weyl nodes, and two nodal lines, exist within 60 millielectron volt of the Fermi level. This work demonstrates that magnetic actinide materials can host strong Nernst and Hall responses due to their combined correlated and topological nature.


2020 ◽  
Vol 310 ◽  
pp. 113839
Author(s):  
Jie Shang ◽  
Yu Liang ◽  
Liu Yang ◽  
Jianwei Li ◽  
Dong Liang
Keyword(s):  
Type I ◽  
Type Ii ◽  

2021 ◽  
Vol 1 ◽  

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.


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