scholarly journals Bosonic crystalline symmetry protected topological phases beyond the group cohomology proposal

2020 ◽  
Vol 101 (16) ◽  
Author(s):  
Hao Song ◽  
Charles Zhaoxi Xiong ◽  
Sheng-Jie Huang
Keyword(s):  
Group Cohomology ◽  
Topological Phases ◽  
Symmetry Protected ◽  
Crystalline Symmetry

scholarly journals Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
S. X. M. Riberolles ◽  
T. V. Trevisan ◽  
B. Kuthanazhi ◽  
T. W. Heitmann ◽  
F. Ye ◽  
...  
Keyword(s):  
Density Functional ◽  
Surface States ◽  
Antiferromagnetic Order ◽  
Functional Theory ◽  
Magnetic Symmetry ◽  
Integer Quantum ◽  
Symmetry Protected ◽  
Topological Crystalline Insulator ◽  
Low Symmetry ◽  
Crystalline Symmetry

AbstractKnowledge of magnetic symmetry is vital for exploiting nontrivial surface states of magnetic topological materials. EuIn2As2 is an excellent example, as it is predicted to have collinear antiferromagnetic order where the magnetic moment direction determines either a topological-crystalline-insulator phase supporting axion electrodynamics or a higher-order-topological-insulator phase with chiral hinge states. Here, we use neutron diffraction, symmetry analysis, and density functional theory results to demonstrate that EuIn2As2 actually exhibits low-symmetry helical antiferromagnetic order which makes it a stoichiometric magnetic topological-crystalline axion insulator protected by the combination of a 180∘ rotation and time-reversal symmetries: $${C}_{2}\times {\mathcal{T}}={2}^{\prime}$$ C 2 × T = 2 ′ . Surfaces protected by $${2}^{\prime}$$ 2 ′ are expected to have an exotic gapless Dirac cone which is unpinned to specific crystal momenta. All other surfaces have gapped Dirac cones and exhibit half-integer quantum anomalous Hall conductivity. We predict that the direction of a modest applied magnetic field of μ0H ≈ 1 to 2 T can tune between gapless and gapped surface states.

scholarly journals Bosonic symmetry-protected topological phases with reflection symmetry

2015 ◽  
Vol 92 (24) ◽  
Author(s):  
Tsuneya Yoshida ◽  
Takahiro Morimoto ◽  
Akira Furusaki
Keyword(s):  
Topological Phases ◽  
Reflection Symmetry ◽  
Symmetry Protected

scholarly journals Universal driving protocol for symmetry-protected Floquet topological phases

2019 ◽  
Vol 99 (24) ◽  
Author(s):  
Bastian Höckendorf ◽  
Andreas Alvermann ◽  
Holger Fehske
Keyword(s):  
Topological Phases ◽  
Symmetry Protected
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