scholarly journals Surface states of massive Dirac fermions with separated Weyl nodes

2016 ◽  
Author(s):  
P. V. Buividovich
Keyword(s):  
Surface States ◽  
Dirac Fermions

Topological Surface States of Dirac Fermions in n-Bi2Te3 –ySey Thermoelectrics

2019 ◽  
Vol 53 (5) ◽  
pp. 647-651
Author(s):  
L. N. Lukyanova ◽  
I. V. Makarenko ◽  
O. A. Usov ◽  
P. A. Dementev
Keyword(s):  
Surface States ◽  
Dirac Fermions ◽  
Topological Surface

scholarly journals Photoemission Spectroscopic Evidence of Multiple Dirac Cones in Superconducting BaSn3

2021 ◽  
Vol 38 (10) ◽  
pp. 107403
Author(s):  
Zhe Huang ◽  
Xianbiao Shi ◽  
Gaoning Zhang ◽  
Zhengtai Liu ◽  
Soohyun Cho ◽  
...  
Keyword(s):  
Surface States ◽  
Photoemission Spectroscopy ◽  
Rotational Axis ◽  
Type I ◽  
Dirac Fermions ◽  
First Principles Calculations ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Topological Quantum ◽  
Topological Surface ◽  
Single Material

Signatures of topological superconductivity (TSC) in superconducting materials with topological nontrivial states prompt intensive researches recently. Utilizing high-resolution angle-resolved photoemission spectroscopy and first-principles calculations, we demonstrate multiple Dirac fermions and surface states in superconductor BaSn3 with a critical transition temperature of about 4.4 K. We predict and then unveil the existence of two pairs of type-I topological Dirac fermions residing on the rotational axis. Type-II Dirac fermions protected by screw axis are confirmed in the same compound. Further calculation for the spin helical texture of the observed surface states originating from the Dirac fermions gives an opportunity for realization of TSC in one single material. Hosting multiple Dirac fermions and topological surface states, the intrinsic superconductor BaSn3 is expected to be a new platform for further investigation of topological quantum materials as well as TSC.

scholarly journals Fermi-crossing Type-II Dirac fermions and topological surface states in NiTe2

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Saumya Mukherjee ◽  
Sung Won Jung ◽  
Sophie F. Weber ◽  
Chunqiang Xu ◽  
Dong Qian ◽  
...  
Keyword(s):  
Surface States ◽  
Dirac Fermions ◽  
Type Ii ◽  
Topological Surface

scholarly journals Термоэлектрические и гальваномагнитные свойства слоистых пленок n-Bi-=SUB=-2-x-=/SUB=-Sb-=SUB=-x-=/SUB=-Te-=SUB=-3-y-=/SUB=-Se-=SUB=-y-=/SUB=-

2019 ◽  
Vol 53 (5) ◽  
pp. 626
Author(s):  
Л.Н. Лукьянова ◽  
О.А. Усов ◽  
М.П. Волков
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Low Temperatures ◽  
Bulk Material ◽  
Surface States ◽  
Dirac Fermions ◽  
Thermoelectric Efficiency ◽  
Strong Magnetic Fields ◽  
Topological Surface ◽  
Magnetoresistance Oscillations

n nanostructured layered films of topological thermoelectrics n-Bi2−xSbxTe3−y Sey , thermoelectric properties in the temperature range of 4.2−300K and magnetoresistance oscillations in strong magnetic fields at low temperatures were studied. It is shown that thermoelectric efficiency in the layered n-Bi2−xSbxTe3−y Sey films increases as compared with bulk material due to both an increase in the Seebeck coefficient at the temperatures below room one, and a decrease in thermal conductivity and weakening of its temperature dependence. From the analysis of magnetoresistance oscillations, the parameters of topological surface states of Dirac fermions were determined and their influence on thermoelectric properties was estimated.

scholarly journals Generation of spin-polarized hot electrons at topological insulators surfaces by scattering from collective charge excitations

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Khalil Zakeri ◽  
Janek Wettstein ◽  
Christoph Sürgers
Keyword(s):  
Topological Insulators ◽  
Spin Asymmetry ◽  
Surface States ◽  
Inelastic Channel ◽  
Dirac Fermions ◽  
Elastic Channel ◽  
Fundamental Physics ◽  
Spintronic Devices ◽  
Spin Polarized ◽  
New Ideas

AbstractTopological insulators (TIs) are materials which exhibit topologically protected electronic surface states, acting as mass-less Dirac fermions. Beside their fascinating fundamental physics, TIs are also promising candidates for future spintronic devices. In this regard, generation of spin-polarized currents in TIs is the first and most important step towards their application in spin-based devices. Here we demonstrate that when electrons are scattered from the surface of bismuth selenide, a prototype TI, not only the elastic channel but also the inelastic channel is strongly spin dependent. In particular collective charge excitations (plasmons) excited at such surfaces show a large spin-dependent electron scattering. Electrons scattered by these excitations exhibit a high spin asymmetry, as high as 40%. The observed effect opens up new possibilities to generate spin-polarized currents at the surface of TIs or utilize the collective charge excitations to analyze the electrons’ spin. The results are also important to understand the spin polarization of the photo-excited electrons excited at TIs surfaces. Moreover, our finding will inspire new ideas for using these plasmonic excitations in the field of spin-plasmonics.

Spin Ordering on the Surface of a Topological Insulator with Magnetic Ions

2012 ◽  
Vol 190 ◽  
pp. 494-497
Author(s):  
V.N. Men'shov ◽  
V.V. Tugushev ◽  
E.V. Chulkov
Keyword(s):  
Topological Insulator ◽  
Chemical Potential ◽  
Mean Field ◽  
Three Dimensional ◽  
Surface States ◽  
Dirac Fermions ◽  
Uniform Magnetization ◽  
Out Of Plane ◽  
Different Temperatures ◽  
Magnetic Ions

We study the effect of magnetic doping on appearance of ferromagnetic (FM) order on the surface of a three-dimensional topological insulator. Assuming the exchange coupling of the Dirac fermions with the dilute magnetic ions, we find that the system under consideration is unstable with respect to a spontaneous uniform magnetization along the out-of-plane direction. The appearance of the magnetization is accompanied by opening of a gap in the spectrum of surface states. In the framework of a mean-field approach, we analyze the possibility of the FM order on the magnetically doped surface of topological insulator at different temperatures and positions of the chemical potential.

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