scholarly journals Non-Abelian band topology in noninteracting metals

Science ◽  
2019 ◽  
Vol 365 (6459) ◽  
pp. 1273-1277 ◽  
Author(s):  
QuanSheng Wu ◽  
Alexey A. Soluyanov ◽  
Tomáš Bzdušek
Keyword(s):  
Nodal Line ◽  
Time Inversion ◽  
Topological Phases ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Energy Bands ◽  
Topological Stability ◽  
One Dimensional ◽  
Biaxial Nematics ◽  
Topological Charges

Electron energy bands of crystalline solids generically exhibit degeneracies called band-structure nodes. Here, we introduce non-Abelian topological charges that characterize line nodes inside the momentum space of crystalline metals with space-time inversion (𝒫𝒯) symmetry and with weak spin-orbit coupling. We show that these are quaternion charges, similar to those describing disclinations in biaxial nematics. Starting from two-band considerations, we develop the complete many-band description of nodes in the presence of 𝒫𝒯 and mirror symmetries, which allows us to investigate the topological stability of nodal chains in metals. The non-Abelian charges put strict constraints on the possible nodal-line configurations. Our analysis goes beyond the standard approach to band topology and implies the existence of one-dimensional topological phases not present in existing classifications.

scholarly journals Effect of Deformation on Topological Properties of Cobalt Monosilicide

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 143
Author(s):  
Sergey Nikolaev ◽  
Dmitry Pshenay-Severin ◽  
Yuri Ivanov ◽  
Alexander Burkov
Keyword(s):  
Band Structure ◽  
Ab Initio Calculations ◽  
Topological Charge ◽  
External Stress ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Topological Properties ◽  
Uniaxial Deformation ◽  
Band Crossing ◽  
Topological Charges

Recently, it was shown that materials with certain crystal structures can exhibit multifold band crossings with large topological charges. CoSi is one such material that belongs to non-centrosymmetric space group P213 (#198) and posseses multifold band crossing points with a topological charge of 4. The change of crystal symmetry, e.g., by means of external stress, can lift the degeneracy and change its topological properties. In the present work, the influence of uniaxial deformation on the band structure and topological properties of CoSi is investigated on the base of ab initio calculations. The k·p Hamiltonian taking into account deformation is constructed on the base of symmetry consideration near the Γ and R points both with and without spin-orbit coupling. The transformation of multifold band crossings into nodes of other types with different topological charges, their shift both in energy and in reciprocal space and the tilt of dispersion around nodes are studied in detail depending on the direction of uniaxial deformation.

scholarly journals Influence of Rashba spin-orbit coupling on the 0- π transition and Kondo temperature in one-dimensional superconductors

2019 ◽  
Vol 100 (23) ◽  
Author(s):  
Ignacio J. Hamad ◽  
Franco T. Lisandrini ◽  
Claudio J. Gazza ◽  
Alejandro M. Lobos
Keyword(s):  
Orbit Coupling ◽  
Kondo Temperature ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
One Dimensional ◽  
Rashba Spin

scholarly journals Topological Nodal Line Electrides: Realization of an Ideal Nodal Line State Nearly Immune from Spin–Orbit Coupling

2019 ◽  
Vol 123 (42) ◽  
pp. 25871-25876 ◽  
Author(s):  
Xiaoming Zhang ◽  
Botao Fu ◽  
Lei Jin ◽  
Xuefang Dai ◽  
Guodong Liu ◽  
...  
Keyword(s):  
Nodal Line ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit

scholarly journals Engineering Topological Nodal Line Semimetals in Rashba Spin-Orbit Coupled Atomic Chains

2019 ◽  
Vol 4 (1) ◽  
pp. 25 ◽  
Author(s):  
Paola Gentile ◽  
Vittorio Benvenuto ◽  
Carmine Ortix ◽  
Canio Noce ◽  
Mario Cuoco
Keyword(s):  
Three Dimensional ◽  
Nodal Line ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Atomic Chain ◽  
Nodal Lines ◽  
Rashba Spin ◽  
Charge Potential ◽  
Atomic Chains ◽  
Two Phases

In this paper, we study an atomic chain in the presence of modulated charge potential and modulated Rashba spin-orbit coupling (RSOC) of equal periods. We show that for commensurate periodicities, λ = 4 n with integer n, the three-dimensional synthetic space obtained by sliding the two phases of the charge potential and RSOC features a topological nodal-line semimetal protected by an anti-unitary particle-hole symmetry. The location and shape of the nodal lines strongly depend on the relative amplitude between the charge potential and RSOC.

Spin–Orbit-Coupling-Induced Type-I/type-II Dirac Nodal-Line Metal in Nonsymmorphic CaSb2

2019 ◽  
Vol 88 (4) ◽  
pp. 044711 ◽  
Author(s):  
Kohei Funada ◽  
Ai Yamakage ◽  
Naoya Yamashina ◽  
Hiroshi Kageyama
Keyword(s):  
Nodal Line ◽  
Orbit Coupling ◽  
Type I ◽  
Spin Orbit Coupling ◽  
Type Ii ◽  
Spin Orbit
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