scholarly journals Origin of spin-polarized photocurrents in the topological surface states of Bi2Se3

2018 ◽  
Vol 98 (15) ◽  
Author(s):  
A. S. Ketterl ◽  
S. Otto ◽  
M. Bastian ◽  
B. Andres ◽  
C. Gahl ◽  
...  
Keyword(s):  
Surface States ◽  
Spin Polarized ◽  
Topological Surface

scholarly journals Deep tuning of photo-thermoelectricity in topological surface states

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shouyuan Huang ◽  
Ireneusz Miotkowski ◽  
Yong P. Chen ◽  
Xianfan Xu
Keyword(s):  
Surface State ◽  
Spin Injection ◽  
Three Dimensional ◽  
Polarized Light ◽  
Surface States ◽  
Linear Dispersion ◽  
Circularly Polarized Light ◽  
Spin Polarized ◽  
Topological Surface ◽  
Topological Surface State

Abstract Three-dimensional topological insulators have been demonstrated in recent years, which possess intriguing gapless, spin-polarized Dirac states with linear dispersion only on the surface. The spin polarization of the topological surface states is also locked to its momentum, which allows controlling motion of electrons using optical helicity, i.e., circularly polarized light. The electrical and thermal transport can also be significantly tuned by the helicity-control of surface state electrons. Here, we report studies of photo-thermoelectric effect of the topological surface states in Bi2Te2Se thin films with large tunability using varied gate voltages and optical helicity. The Seebeck coefficient can be altered by more than five times compared to the case without spin injection. This deep tuning is originated from the optical helicity-induced photocurrent which is shown to be enhanced, reduced, turned off, and even inverted due to the change of the accessed band structures by electrical gating. The helicity-selected topological surface state thus has a large effect on thermoelectric transport, demonstrating great opportunities for realizing helicity control of optoelectronic and thermal devices.

scholarly journals A Review of Topological Semimetal Phases in Photonic Artificial Microstructures

2021 ◽  
Vol 9 ◽  
Author(s):  
Boyang Xie ◽  
Hui Liu ◽  
Haonan Wang ◽  
Hua Cheng ◽  
Jianguo Tian ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Electromagnetic Waves ◽  
Three Dimensional ◽  
Surface States ◽  
Band Structures ◽  
Nodal Lines ◽  
Anomalous Reflection ◽  
Spin Polarized ◽  
Topological Semimetal ◽  
Topological Surface

In the past few years, the concept of topological matter has inspired considerable research in broad areas of physics. In particular, photonic artificial microstructures like photonic crystals and metamaterials provide a unique platform to investigate topologically non-trivial physics in spin-1 electromagnetic fields. Three-dimensional (3D) topological semimetal band structures, which carry non-trivial topological charges, are fundamental to 3D topological physics. Here, we review recent progress in understanding 3D photonic topological semimetal phases and various approaches for realizing them, especially with photonic crystals or metamaterials. We review topological gapless band structures and topological surface states aroused from the non-trivial bulk topology. Weyl points, 3D Dirac points, nodal lines, and nodal surfaces of different types are discussed. We also demonstrate their application in coupling spin-polarized electromagnetic waves, anomalous reflection, vortex beams generation, bulk transport, and non-Hermitian effects.

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.

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 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.

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