scholarly journals Optical conductivity signatures of open Dirac nodal lines

2021 ◽  
Vol 104 (20) ◽  
Author(s):  
David Santos-Cottin ◽  
Michele Casula ◽  
Luca de' Medici ◽  
F. Le Mardelé ◽  
J. Wyzula ◽  
...  
Keyword(s):  
Optical Conductivity ◽  
Nodal Lines

scholarly journals Optical signatures of Dirac nodal lines in NbAs2

2018 ◽  
Vol 116 (4) ◽  
pp. 1168-1173 ◽  
Author(s):  
Yinming Shao ◽  
Zhiyuan Sun ◽  
Ying Wang ◽  
Chenchao Xu ◽  
Raman Sankar ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Power Law ◽  
Optical Conductivity ◽  
Dominant Role ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Nodal Lines ◽  
Energy Gaps ◽  
Conductivity Spectra

Using polarized optical and magneto-optical spectroscopy, we have demonstrated universal aspects of electrodynamics associated with Dirac nodal lines that are found in several classes of unconventional intermetallic compounds. We investigated anisotropic electrodynamics of NbAs2 where the spin-orbit coupling (SOC) triggers energy gaps along the nodal lines. These gaps manifest as sharp steps in the optical conductivity spectra σ1(ω). This behavior is followed by the linear power-law scaling of σ1(ω) at higher frequencies, consistent with our theoretical analysis for dispersive Dirac nodal lines. Magneto-optics data affirm the dominant role of nodal lines in the electrodynamics of NbAs2.

scholarly journals Dirac nodal lines protected against spin-orbit interaction in IrO2

2019 ◽  
Vol 3 (6) ◽  
Author(s):  
J. N. Nelson ◽  
J. P. Ruf ◽  
Y. Lee ◽  
C. Zeledon ◽  
J. K. Kawasaki ◽  
...  
Keyword(s):  
Orbit Interaction ◽  
Spin Orbit ◽  
Spin Orbit Interaction ◽  
Nodal Lines

scholarly journals Enhancement of the transverse thermoelectric conductivity originating from stationary points in nodal lines

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

scholarly journals Cobalt-based magnetic Weyl semimetals with high-thermodynamic stabilities

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Wei Luo ◽  
Yuma Nakamura ◽  
Jinseon Park ◽  
Mina Yoon
Keyword(s):  
Tight Binding ◽  
Three Dimensional ◽  
Interlayer Coupling ◽  
First Principles Calculation ◽  
Optimization Approach ◽  
Binding Model ◽  
Nodal Lines ◽  
Weyl Semimetal ◽  
Topological Quantum ◽  
First Time

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.

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.

scholarly journals Broadband optical conductivity of the chiral multifold semimetal PdGa

2021 ◽  
Vol 103 (11) ◽  
Author(s):  
L. Z. Maulana ◽  
Z. Li ◽  
E. Uykur ◽  
K. Manna ◽  
S. Polatkan ◽  
...  
Keyword(s):  
Optical Conductivity

scholarly journals Linear behavior of the optical conductivity and incoherent charge transport in BaCoS2

2018 ◽  
Vol 2 (10) ◽  
Author(s):  
D. Santos-Cottin ◽  
Y. Klein ◽  
Ph. Werner ◽  
T. Miyake ◽  
L. de' Medici ◽  
...  
Keyword(s):  
Charge Transport ◽  
Optical Conductivity ◽  
Linear Behavior

scholarly journals Low-Energy Optical Conductivity of TaP: Comparison of Theory and Experiment

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 567
Author(s):  
Alexander Yaresko ◽  
Artem V. Pronin
Keyword(s):  
Experimental Data ◽  
Optical Conductivity ◽  
Low Energy ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Natural Explanation ◽  
Weyl Semimetal ◽  
Unintentional Doping ◽  
Mott Formula ◽  
Theory And Experiment

The ab-plane optical conductivity of the Weyl semimetal TaP is calculated from the band structure and compared to the experimental data. The overall agreement between theory and experiment is found to be best when the Fermi level is slightly (20 to 60 meV) shifted upwards in the calculations. This confirms a small unintentional doping of TaP, reported earlier, and allows a natural explanation of the strong low-energy (50 meV) peak seen in the experimental ab-plane optical conductivity: this peak originates from transitions between the almost parallel non-degenerate electronic bands split by spin-orbit coupling. The temperature evolution of the peak can be reasonably well reproduce by calculations using an analog of the Mott formula.

scholarly journals Symmetry-protected nodal points and nodal lines in magnetic materials

2021 ◽  
Vol 103 (24) ◽  
Author(s):  
Jian Yang ◽  
Chen Fang ◽  
Zheng-Xin Liu
Keyword(s):  
Magnetic Materials ◽  
Nodal Lines ◽  
Nodal Points ◽  
Symmetry Protected
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