scholarly journals Phase diagrams of superconducting topological surface states

2021 ◽  
Vol 24 (4) ◽  
pp. 43701
Author(s):  
W. Zhao ◽  
L. Ding ◽  
B. Zhou ◽  
J. Wu ◽  
Y. Bai ◽  
...  
Keyword(s):  
Phase Diagrams ◽  
Time Reversal ◽  
Mirror Symmetry ◽  
Surface States ◽  
Time Reversal Symmetry ◽  
And Topology ◽  
Topological Surface ◽  
Iron Based ◽  
Crystalline Symmetry

In this paper, we present a detailed study on the phase diagrams of superconducting topological surface states, especially, focusing on the interplay between crystalline symmetry and topology of the effective BdG Hamiltonian. We show that for the 4 x 4 kinematic Hamiltonian of the normal state, a mirror symmetry M can be defined, and for the M-odd pairings, the classification of the 8 x 8 BdG Hamiltonian is ℤ⊕ℤ, and the time-reversal symmetry is broken intrinsically. The topological non-trivial phase can support chiral Majorana edge modes, and can be realized in the thin films of iron-based superconductor such as FeSeTe.

scholarly journals Experimental Demonstration of Topological Surface States Protected by Time-Reversal Symmetry

2009 ◽  
Vol 103 (26) ◽  
Author(s):  
Tong Zhang ◽  
Peng Cheng ◽  
Xi Chen ◽  
Jin-Feng Jia ◽  
Xucun Ma ◽  
...  
Keyword(s):  
Time Reversal ◽  
Surface States ◽  
Time Reversal Symmetry ◽  
Experimental Demonstration ◽  
Topological Surface

scholarly journals Topological crystalline insulator nanostructures

Nanoscale ◽  
2014 ◽  
Vol 6 (23) ◽  
pp. 14133-14140 ◽  
Author(s):  
Jie Shen ◽  
Judy J. Cha
Keyword(s):  
Time Reversal ◽  
Topological Insulators ◽  
Surface States ◽  
Time Reversal Symmetry ◽  
Topological Crystalline Insulators ◽  
Topological Crystalline Insulator ◽  
Crystalline Symmetry

Topological crystalline insulators are topological insulators whose surface states are protected by the crystalline symmetry, instead of the time reversal symmetry.

scholarly journals Discovery of a weak topological insulating state and van Hove singularity in triclinic RhBi2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kyungchan Lee ◽  
Gunnar F. Lange ◽  
Lin-Lin Wang ◽  
Brinda Kuthanazhi ◽  
Thaís V. Trevisan ◽  
...  
Keyword(s):  
Time Reversal ◽  
Topological Insulators ◽  
Dirac Point ◽  
Saddle Points ◽  
Surface States ◽  
Van Hove Singularity ◽  
Space Group ◽  
Topological Materials ◽  
Topological Surface ◽  
Optimal Space

AbstractTime reversal symmetric (TRS) invariant topological insulators (TIs) fullfil a paradigmatic role in the field of topological materials, standing at the origin of its development. Apart from TRS protected strong TIs, it was realized early on that more confounding weak topological insulators (WTI) exist. WTIs depend on translational symmetry and exhibit topological surface states only in certain directions making it significantly more difficult to match the experimental success of strong TIs. We here report on the discovery of a WTI state in RhBi2 that belongs to the optimal space group P$$\bar{1}$$ 1 ¯ , which is the only space group where symmetry indicated eigenvalues enumerate all possible invariants due to absence of additional constraining crystalline symmetries. Our ARPES, DFT calculations, and effective model reveal topological surface states with saddle points that are located in the vicinity of a Dirac point resulting in a van Hove singularity (VHS) along the (100) direction close to the Fermi energy (EF). Due to the combination of exotic features, this material offers great potential as a material platform for novel quantum effects.

scholarly journals Mechanism for a pairing state with time-reversal symmetry breaking in iron-based superconductors

2012 ◽  
Vol 85 (18) ◽  
Author(s):  
Christian Platt ◽  
Ronny Thomale ◽  
Carsten Honerkamp ◽  
Shou-Cheng Zhang ◽  
Werner Hanke
Keyword(s):  
Symmetry Breaking ◽  
Time Reversal ◽  
Time Reversal Symmetry ◽  
Iron Based Superconductors ◽  
Pairing State ◽  
Iron Based

scholarly journals Manifestation of axion electrodynamics through magnetic ordering on edges of a topological insulator

2015 ◽  
Vol 112 (37) ◽  
pp. 11514-11518 ◽  
Author(s):  
Yea-Lee Lee ◽  
Hee Chul Park ◽  
Jisoon Ihm ◽  
Young-Woo Son
Keyword(s):  
Electric Field ◽  
Topological Insulator ◽  
Time Reversal ◽  
First Principles ◽  
Surface States ◽  
Magnetic Ordering ◽  
Crystal Face ◽  
Magnetic Dipoles ◽  
Topological Surface ◽  
The Difference

Because topological surface states of a single-crystal topological insulator can exist on all surfaces with different crystal orientations enclosing the crystal, mutual interactions among those states contiguous to each other through edges can lead to unique phenomena inconceivable in normal insulators. Here we show, based on a first-principles approach, that the difference in the work function between adjacent surfaces with different crystal-face orientations generates a built-in electric field around facet edges of a prototypical topological insulator such as Bi2Se3. Owing to the topological magnetoelectric coupling for a given broken time-reversal symmetry in the crystal, the electric field, in turn, forces effective magnetic dipoles to accumulate along the edges, realizing the facet-edge magnetic ordering. We demonstrate that the predicted magnetic ordering is in fact a manifestation of the axion electrodynamics in real solids.

scholarly journals Three-Dimensional Topological States of Phonons with Tunable Pseudospin Physics

Research ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Yizhou Liu ◽  
Yong Xu ◽  
Wenhui Duan
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Surface States ◽  
Phonon Transport ◽  
Efficient Control ◽  
Topological States ◽  
Topological Surface ◽  
Symmetry Protected ◽  
Energy Information ◽  
Crystalline Symmetry

Efficient control of phonons is crucial to energy-information technology, but limited by the lacking of tunable degrees of freedom like charge or spin. Here we suggest to utilize crystalline symmetry-protected pseudospins as new quantum degrees of freedom to manipulate phonons. Remarkably, we reveal a duality between phonon pseudospins and electron spins by presenting Kramers-like degeneracy and pseudospin counterparts of spin-orbit coupling, which lays the foundation for “pseudospin phononics”. Furthermore, we report two types of three-dimensional phononic topological insulators, which give topologically protected, gapless surface states with linear and quadratic band degeneracies, respectively. These topological surface states display unconventional phonon transport behaviors attributed to the unique pseudospin-momentum locking, which are useful for phononic circuits, transistors, antennas, etc. The emerging pseudospin physics offers new opportunities to develop future phononics.

scholarly journals Cubic 3D Chern photonic insulators with orientable large Chern vectors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chiara Devescovi ◽  
Mikel García-Díez ◽  
Iñigo Robredo ◽  
María Blanco de Paz ◽  
Jon Lasa-Alonso ◽  
...  
Keyword(s):  
Time Reversal ◽  
Degrees Of Freedom ◽  
Surface States ◽  
Magnetic Response ◽  
Time Reversal Symmetry ◽  
General Strategy ◽  
Topological Phases ◽  
Magnetization Axis ◽  
Opening Up ◽  
Internal Symmetries

AbstractTime Reversal Symmetry (TRS) broken topological phases provide gapless surface states protected by topology, regardless of additional internal symmetries, spin or valley degrees of freedom. Despite the numerous demonstrations of 2D topological phases, few examples of 3D topological systems with TRS breaking exist. In this article, we devise a general strategy to design 3D Chern insulating (3D CI) cubic photonic crystals in a weakly TRS broken environment with orientable and arbitrarily large Chern vectors. The designs display topologically protected chiral and unidirectional surface states with disjoint equifrequency loops. The resulting crystals present the following characteristics: First, by increasing the Chern number, multiple surface states channels can be supported. Second, the Chern vector can be oriented along any direction simply changing the magnetization axis, opening up larger 3D CI/3D CI interfacing possibilities as compared to 2D. Third, by lowering the TRS breaking requirements, the system is ideal for realistic photonic applications where the magnetic response is weak.

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