scholarly journals Observation of surface states on heavily indium-doped SnTe(111), a superconducting topological crystalline insulator

2016 ◽  
Vol 93 (7) ◽  
Author(s):  
C. M. Polley ◽  
V. Jovic ◽  
T.-Y. Su ◽  
M. Saghir ◽  
D. Newby ◽  
...  
Keyword(s):  
Surface States ◽  
Topological Crystalline Insulator

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 Erratum: Observation of ultrahigh mobility surface states in a topological crystalline insulator by infrared spectroscopy

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Ying Wang ◽  
Guoyu Luo ◽  
Junwei Liu ◽  
R. Sankar ◽  
Nan-Lin Wang ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Surface States ◽  
Topological Crystalline Insulator

A methodical study of quantum phase engineering in topological crystalline insulator SnTe and related alloys

2019 ◽  
Vol 21 (38) ◽  
pp. 21633-21650 ◽  
Author(s):  
Mohsen Yarmohammadi ◽  
Kavoos Mirabbaszadeh
Keyword(s):  
Detailed Analysis ◽  
Surface States ◽  
Quantum Phase ◽  
Phase Engineering ◽  
Topological Crystalline Insulator

A detailed analysis of the perturbation effects on the quantum phase of SnTe(001) surface states.

scholarly journals Strain-tuning of Dirac states at the SnTe (001) surface

2015 ◽  
Author(s):  
Matthias Drüppel ◽  
Peter Kruger ◽  
Michael Rohlfing
Keyword(s):  
Density Functional Theory ◽  
Time Reversal ◽  
Density Functional ◽  
Displacement Vector ◽  
Surface States ◽  
Functional Theory ◽  
Bulk Properties ◽  
Invariant Points ◽  
Topological Crystalline Insulator ◽  
Crystalline Symmetry

The topological crystalline insulator SnTe belongs to the recently discovered class of materials in which a crystalline symmetry ensures the existence of topologically protected Dirac like surface states. In contrast to topological insulators, this symmetry can be broken via deformations of the crystal. This opens up new possibilities of manipulating the Dirac states and inducing a controllable gap. Here, we have employed density-functional theory to investigate the response of the Dirac states to lattice deformations [1]. The (001) surface exhibits four Dirac cones which lie at non-time-reversal-invariant points close to X, along the projection of the (110) and (110) mirror planes. Our calculations show that a gap of up to approx 30 meV can be introduced via lattice deformations that break at least one of these mirror symmetries. Remarkably, distortions at the surface only can already open up the gap, even though bulk properties are not changed. The gap is formed at either all four or just two cones, depending on the direction of the displacement vector, making it possible to create a state where gaped and non-gaped Dirac cones coexist. Notably, if the whole slab is distorted, bulk bands are being pushed into the gap making the whole system metallic. [1] M. Drüppel et al, Phys. Rev. B 90, 155312 (2014)

scholarly journals Strain engineering Dirac surface states in heteroepitaxial topological crystalline insulator thin films

2015 ◽  
Vol 10 (10) ◽  
pp. 849-853 ◽  
Author(s):  
Ilija Zeljkovic ◽  
Daniel Walkup ◽  
Badih A. Assaf ◽  
Kane L. Scipioni ◽  
R. Sankar ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface States ◽  
Strain Engineering ◽  
Topological Crystalline Insulator

scholarly journals Discovery of $${\hat{\boldsymbol{C}}}_2$$ rotation anomaly in topological crystalline insulator SrPb

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenhui Fan ◽  
Simin Nie ◽  
Cuixiang Wang ◽  
Binbin Fu ◽  
Changjiang Yi ◽  
...  
Keyword(s):  
Surface States ◽  
Binary Compound ◽  
Dirac Fermions ◽  
Rotation Symmetry ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Topological Crystalline Insulators ◽  
Topological Crystalline Insulator ◽  
Nontrivial Topology ◽  
Bulk Band

AbstractTopological crystalline insulators (TCIs) are insulating electronic states with nontrivial topology protected by crystalline symmetries. Recently, theory has proposed new classes of TCIs protected by rotation symmetries $$\hat C_n$$ C ̂ n , which have surface rotation anomaly evading the fermion doubling theorem, i.e., n instead of 2n Dirac cones on the surface preserving the rotation symmetry. Here, we report the first realization of the $$\hat C_2$$ C ̂ 2 rotation anomaly in a binary compound SrPb. Our first-principles calculations reveal two massless Dirac fermions protected by the combination of time-reversal symmetry $$\hat T$$ T ̂ and $$\hat C_{2y}$$ C ̂ 2 y on the (010) surface. Using angle-resolved photoemission spectroscopy, we identify two Dirac surface states inside the bulk band gap of SrPb, confirming the $$\hat C_2$$ C ̂ 2 rotation anomaly in the new classes of TCIs. The findings enrich the classification of topological phases, which pave the way for exploring exotic behavior of the new classes of TCIs.

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