scholarly journals Topological semimetals protected by off-centered symmetries in nonsymmorphic crystals

2017 ◽  
Vol 95 (7) ◽  
Author(s):  
Bohm-Jung Yang ◽  
Troels Arnfred Bojesen ◽  
Takahiro Morimoto ◽  
Akira Furusaki
Keyword(s):  
Topological Semimetals

scholarly journals Linear and nonlinear optical responses in the chiral multifold semimetal RhSi

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Zhuoliang Ni ◽  
B. Xu ◽  
M.-Á. Sánchez-Martínez ◽  
Y. Zhang ◽  
K. Manna ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Chemical Potential ◽  
Technological Development ◽  
Optical Responses ◽  
Chiral Magnetic Effect ◽  
Hole Band ◽  
Linear And Nonlinear ◽  
Characteristic Features ◽  
Topological Semimetals ◽  
Terahertz Emission Spectroscopy

AbstractChiral topological semimetals are materials that break both inversion and mirror symmetries. They host interesting phenomena such as the quantized circular photogalvanic effect (CPGE) and the chiral magnetic effect. In this work, we report a comprehensive theoretical and experimental analysis of the linear and nonlinear optical responses of the chiral topological semimetal RhSi, which is known to host multifold fermions. We show that the characteristic features of the optical conductivity, which display two distinct quasi-linear regimes above and below 0.4 eV, can be linked to excitations of different kinds of multifold fermions. The characteristic features of the CPGE, which displays a sign change at 0.4 eV and a large non-quantized response peak of around 160 μA/V2 at 0.7 eV, are explained by assuming that the chemical potential crosses a flat hole band at the Brillouin zone center. Our theory predicts that, in order to observe a quantized CPGE in RhSi, it is necessary to increase the chemical potential as well as the quasiparticle lifetime. More broadly, our methodology, especially the development of the broadband terahertz emission spectroscopy, could be widely applied to study photogalvanic effects in noncentrosymmetric materials and in topological insulators in a contact-less way and accelerate the technological development of efficient infrared detectors based on topological semimetals.

scholarly journals High-frequency rectifiers based on type-II Dirac fermions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Libo Zhang ◽  
Zhiqingzi Chen ◽  
Kaixuan Zhang ◽  
Lin Wang ◽  
Huang Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
Dynamic Range ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Anisotropy Ratio ◽  
Dirac Fermions ◽  
Topological States ◽  
Topological Semimetals ◽  
Polarized Surface ◽  
Symmetry Protected

AbstractThe advent of topological semimetals enables the exploitation of symmetry-protected topological phenomena and quantized transport. Here, we present homogeneous rectifiers, converting high-frequency electromagnetic energy into direct current, based on low-energy Dirac fermions of topological semimetal-NiTe2, with state-of-the-art efficiency already in the first implementation. Explicitly, these devices display room-temperature photosensitivity as high as 251 mA W−1 at 0.3 THz in an unbiased mode, with a photocurrent anisotropy ratio of 22, originating from the interplay between the spin-polarized surface and bulk states. Device performances in terms of broadband operation, high dynamic range, as well as their high sensitivity, validate the immense potential and unique advantages associated to the control of nonequilibrium gapless topological states via built-in electric field, electromagnetic polarization and symmetry breaking in topological semimetals. These findings pave the way for the exploitation of topological phase of matter for high-frequency operations in polarization-sensitive sensing, communications and imaging.

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 Topological Semimetals Studied by Ab Initio Calculations

2018 ◽  
Vol 87 (4) ◽  
pp. 041002 ◽  
Author(s):  
Motoaki Hirayama ◽  
Ryo Okugawa ◽  
Shuichi Murakami
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Topological Semimetals

scholarly journals Erratum: Spin Chirality Tuning and Topological Semimetals in StrainedHgTexS1−x[Phys. Rev. Lett.114, 236805 (2015)]

2016 ◽  
Vol 116 (19) ◽  
Author(s):  
Tomáš Rauch ◽  
Steven Achilles ◽  
Jürgen Henk ◽  
Ingrid Mertig
Keyword(s):  
Topological Semimetals

scholarly journals Catalog of magnetic topological semimetals

AIP Advances ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 095222
Author(s):  
Md. Rakibul Karim Akanda
Keyword(s):  
Topological Semimetals

scholarly journals Dirac nodal surfaces and nodal lines in ZrSiS

2019 ◽  
Vol 5 (5) ◽  
pp. eaau6459 ◽  
Author(s):  
B.-B. Fu ◽  
C.-J. Yi ◽  
T.-T. Zhang ◽  
M. Caputo ◽  
J.-Z. Ma ◽  
...  
Keyword(s):  
Photoemission Spectroscopy ◽  
Dirac Fermions ◽  
Fermi Surfaces ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Nodal Lines ◽  
Nodal Points ◽  
Different Dimensions ◽  
Topological Semimetals ◽  
Symmetry Protected ◽  
Nodal Surfaces

Topological semimetals are characterized by symmetry-protected band crossings, which can be preserved in different dimensions in momentum space, forming zero-dimensional nodal points, one-dimensional nodal lines, or even two-dimensional nodal surfaces. Materials harboring nodal points and nodal lines have been experimentally verified, whereas experimental evidence of nodal surfaces is still lacking. Here, using angle-resolved photoemission spectroscopy (ARPES), we reveal the coexistence of Dirac nodal surfaces and nodal lines in the bulk electronic structures of ZrSiS. As compared with previous ARPES studies on ZrSiS, we obtained pure bulk states, which enable us to extract unambiguously intrinsic information of the bulk nodal surfaces and nodal lines. Our results show that the nodal lines are the only feature near the Fermi level and constitute the whole Fermi surfaces. We not only prove that the low-energy quasiparticles in ZrSiS are contributed entirely by Dirac fermions but also experimentally realize the nodal surface in topological semimetals.

scholarly journals Films of rhombohedral graphite as two-dimensional topological semimetals

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Sergey Slizovskiy ◽  
Edward McCann ◽  
Mikito Koshino ◽  
Vladimir I. Fal’ko
Keyword(s):  
Thin Films ◽  
Anomalous Hall Effect ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Berry Curvature ◽  
Electrostatic Gating ◽  
Topological Semimetals ◽  
Intrinsic Magnetic Moment

AbstractTopologically non-trivial states appear in a number of materials ranging from spin-orbit-coupling driven topological insulators to graphene. In multivalley conductors, such as mono- and bilayer graphene, despite a zero total Chern number for the entire Brillouin zone, Berry curvature with different signs concentrated in different valleys can affect the material’s transport characteristics. Here we consider thin films of rhombohedral graphite, which appear to retain truly two-dimensional properties up to tens of layers of thickness and host two-dimensional electron states with a large Berry curvature, accompanied by a giant intrinsic magnetic moment carried by electrons. The size of Berry curvature and magnetization in the vicinity of each valley can be controlled by electrostatic gating leading to a tuneable anomalous Hall effect and a peculiar structure of the two-dimensional Landau level spectrum.

scholarly journals Two-dimensional topological semimetals protected by symmorphic symmetries

2020 ◽  
Vol 101 (19) ◽  
Author(s):  
Wei Luo ◽  
Junyi Ji ◽  
Jinlian Lu ◽  
Xiuwen Zhang ◽  
Hongjun Xiang
Keyword(s):  
Two Dimensional ◽  
Topological Semimetals
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