scholarly journals Topological surface states above the Fermi level in Hf2Te2P

2019 ◽  
Vol 100 (8) ◽  
Author(s):  
T. J. Boyle ◽  
A. Rossi ◽  
M. Walker ◽  
P. Carlson ◽  
M. K. Miller ◽  
...  
Keyword(s):  
Fermi Level ◽  
Surface States ◽  
Topological Surface

Fermi level tuning and the robustness of topological surface states against impurity doping in Sn doped Sb2Te2Se

2021 ◽  
Vol 118 (15) ◽  
pp. 154001
Author(s):  
Debarghya Mallick ◽  
Shoubhik Mandal ◽  
R. Ganesan ◽  
P. S. Anil Kumar
Keyword(s):  
Fermi Level ◽  
Surface States ◽  
Impurity Doping ◽  
Topological Surface

scholarly journals Strongly correlated superconductor with polytypic 3D Dirac points

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Sergey Borisenko ◽  
Volodymyr Bezguba ◽  
Alexander Fedorov ◽  
Yevhen Kushnirenko ◽  
Vladimir Voroshnin ◽  
...  
Keyword(s):  
Fermi Level ◽  
Density Functional ◽  
Energy Gap ◽  
Surface States ◽  
Flat Band ◽  
Type I ◽  
Exact Matching ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Topological Superconductors ◽  
Topological Surface

Abstract Topological superconductors should be able to provide essential ingredients for quantum computing, but are very challenging to realize. Spin–orbit interaction in iron-based superconductors opens the energy gap between the p-states of pnictogen and d-states of iron very close to the Fermi level, and such p-states have been recently experimentally detected. Density-functional theory predicts existence of topological surface states within this gap in FeTe1−xSex making it an attractive candidate material. Here we use synchrotron-based angle-resolved photoemission spectroscopy and band structure calculations to demonstrate that FeTe1−xSex (x = 0.45) is a superconducting 3D Dirac semimetal hosting type-I and type-II Dirac points and that its electronic structure remains topologically trivial. We show that the inverted band gap in FeTe1−xSex can possibly be realized by further increase of Te content, but strong correlations reduce it to a sub-meV size, making the experimental detection of this gap and corresponding topological surface states very challenging, not to mention exact matching with the Fermi level. On the other hand, the p–d and d–d interactions are responsible for the formation of extremely flat band at the Fermi level pointing to its intimate relation with the mechanism of high-Tc superconductivity in IBS.

Large Damping Enhancement in Dirac‐Semimetal–Ferromagnetic‐Metal Layered Structures Caused by Topological Surface States

2021 ◽  
pp. 2008411
Author(s):  
Jinjun Ding ◽  
Chuanpu Liu ◽  
Yuejie Zhang ◽  
Vijaysankar Kalappattil ◽  
Rui Yu ◽  
...  
Keyword(s):  
Surface States ◽  
Layered Structures ◽  
Ferromagnetic Metal ◽  
Dirac Semimetal ◽  
Topological Surface

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 2D weak anti-localization in thin films of the topological semimetal Pd$$_{3}$$Bi$$_{2}$$S$$_{2}$$

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shama ◽  
R. K. Gopal ◽  
Goutam Sheet ◽  
Yogesh Singh
Keyword(s):  
Thin Films ◽  
Phonon Scattering ◽  
Surface States ◽  
Relaxation Mechanism ◽  
Transport Studies ◽  
Bulk Carriers ◽  
Topological Semimetal ◽  
Topological Surface ◽  
First Time ◽  
Electron Phonon Scattering

AbstractPd$$_{3}$$ 3 Bi$$_{2}$$ 2 S$$_{2}$$ 2 (PBS) is a recently proposed topological semimetal candidate. However, evidence for topological surface states have not yet been revealed in transport measurements due to the large mobility of bulk carriers. We report the growth and magneto-transport studies of PBS thin films where the mobility of the bulk carriers is reduced by two orders of magnitude, revealing for the first time, contributions from the 2-dimensional (2D) topological surface states in the observation of the 2D weak anti-localization (WAL) effect in magnetic field and angle dependent conductivity measurements. The magnetotransport data is analysed within the 2D Hikami-Larkin-Nagaoka (HLN) theory. The analysis suggests that multiple conduction channels contribute to the transport. It is also found that the temperature dependence of the dephasing length can’t be explained only by electron-electron scattering and that electron-phonon scattering also contributes to the phase relaxation mechanism in PBS films.

scholarly journals Strain driven emergence of topological non-triviality in YPdBi thin films

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vishal Bhardwaj ◽  
Anupam Bhattacharya ◽  
Shivangi Srivastava ◽  
Vladimir V. Khovaylo ◽  
Jhuma Sannigrahi ◽  
...  
Keyword(s):  
Thin Films ◽  
Heavy Fermion ◽  
Critical Role ◽  
Surface States ◽  
Strain Engineering ◽  
Emergent Properties ◽  
Spintronic Devices ◽  
Topological States ◽  
Topological Surface ◽  
Strained Films

AbstractHalf-Heusler compounds exhibit a remarkable variety of emergent properties such as heavy-fermion behaviour, unconventional superconductivity and magnetism. Several of these compounds have been predicted to host topologically non-trivial electronic structures. Remarkably, recent theoretical studies have indicated the possibility to induce non-trivial topological surface states in an otherwise trivial half-Heusler system by strain engineering. Here, using magneto-transport measurements and first principles DFT-based simulations, we demonstrate topological surface states on strained [110] oriented thin films of YPdBi grown on (100) MgO. These topological surface states arise in an otherwise trivial semi-metal purely driven by strain. Furthermore, we observe the onset of superconductivity in these strained films highlighting the possibility of engineering a topological superconducting state. Our results demonstrate the critical role played by strain in engineering novel topological states in thin film systems for developing next-generation spintronic devices.

Structural stability and topological surface states of the SnTe (111) surface

2014 ◽  
Vol 89 (12) ◽  
Author(s):  
Jianfeng Wang ◽  
Junwei Liu ◽  
Yong Xu ◽  
Jian Wu ◽  
Bing-Lin Gu ◽  
...  
Keyword(s):  
Structural Stability ◽  
Surface States ◽  
Topological Surface

scholarly journals Topological surface states of Bi2Se3coexisting with Se vacancies

2012 ◽  
Vol 7 (1-2) ◽  
pp. 148-150 ◽  
Author(s):  
Binghai Yan ◽  
Delin Zhang ◽  
Claudia Felser
Keyword(s):  
Surface States ◽  
Topological Surface
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