scholarly journals Quasiparticle Interference ofC2-Symmetric Surface States in a LaOFeAs Parent Compound

2011 ◽  
Vol 106 (8) ◽  
Author(s):  
Xiaodong Zhou ◽  
Cun Ye ◽  
Peng Cai ◽  
Xiangfeng Wang ◽  
Xianhui Chen ◽  
...  
Keyword(s):  
Parent Compound ◽  
Surface States ◽  
Quasiparticle Interference ◽  
Symmetric Surface

scholarly journals Quasiparticle interference of surface states in the type-II Weyl semimetal WTe2

2017 ◽  
Vol 96 (16) ◽  
Author(s):  
Wenhan Zhang ◽  
Quansheng Wu ◽  
Lunyong Zhang ◽  
Sang-Wook Cheong ◽  
Alexey A. Soluyanov ◽  
...  
Keyword(s):  
Surface States ◽  
Type Ii ◽  
Quasiparticle Interference ◽  
Weyl Semimetal

scholarly journals Quasiparticle interference evidence of the topological Fermi arc states in chiral fermionic semimetal CoSi

2019 ◽  
Vol 5 (12) ◽  
pp. eaaw9485 ◽  
Author(s):  
Qian-Qian Yuan ◽  
Liqin Zhou ◽  
Zhi-Cheng Rao ◽  
Shangjie Tian ◽  
Wei-Min Zhao ◽  
...  
Keyword(s):  
Density Functional ◽  
Surface States ◽  
High Energy ◽  
Scanning Tunneling ◽  
Wide Energy Range ◽  
Tunneling Microscopy ◽  
Space Resolution ◽  
Fermi Arc ◽  
Quasiparticle Interference ◽  
High Space

Chiral fermions in solid state feature “Fermi arc” states, connecting the surface projections of the bulk chiral nodes. The surface Fermi arc is a signature of nontrivial bulk topology. Unconventional chiral fermions with an extensive Fermi arc traversing the whole Brillouin zone have been theoretically proposed in CoSi. Here, we use scanning tunneling microscopy/spectroscopy to investigate quasiparticle interference at various terminations of a CoSi single crystal. The observed surface states exhibit chiral fermion–originated characteristics. These reside on (001) and (011) but not (111) surfaces with p-rotation symmetry, spiral with energy, and disperse in a wide energy range from ~−200 to ~+400 mV. Owing to the high-energy and high-space resolution, a spin-orbit coupling–induced splitting of up to ~80 mV is identified. Our observations are corroborated by density functional theory and provide strong evidence that CoSi hosts the unconventional chiral fermions and the extensive Fermi arc states.

scholarly journals Surface states and quasiparticle interference in Bernal and rhombohedral graphite with and without trigonal warping

2021 ◽  
Vol 104 (15) ◽  
Author(s):  
Vardan Kaladzhyan ◽  
Sarah Pinon ◽  
Frédéric Joucken ◽  
Zhehao Ge ◽  
Eberth A. Quezada-Lopez ◽  
...  
Keyword(s):  
Surface States ◽  
Quasiparticle Interference ◽  
Trigonal Warping

scholarly journals Pressure-induced superconductivity in topological parent compound Bi2Te3

2010 ◽  
Vol 108 (1) ◽  
pp. 24-28 ◽  
Author(s):  
J. L. Zhang ◽  
S. J. Zhang ◽  
H. M. Weng ◽  
W. Zhang ◽  
L. X. Yang ◽  
...  
Keyword(s):  
High Pressure ◽  
Parent Compound ◽  
Surface States ◽  
Structural Data ◽  
X Ray Diffraction ◽  
Hall Effects ◽  
Structure Phase Transition ◽  
Diffraction Patterns ◽  
Structure Investigations ◽  
Successful Observation

We report a successful observation of pressure-induced superconductivity in a topological compound Bi2Te3 with Tc of ∼3 K between 3 to 6 GPa. The combined high-pressure structure investigations with synchrotron radiation indicated that the superconductivity occurred at the ambient phase without crystal structure phase transition. The Hall effects measurements indicated the hole-type carrier in the pressure-induced superconducting Bi2Te3 single crystal. Consequently, the first-principles calculations based on the structural data obtained by the Rietveld refinement of X-ray diffraction patterns at high pressure showed that the electronic structure under pressure remained topologically nontrivial. The results suggested that topological superconductivity can be realized in Bi2Te3 due to the proximity effect between superconducting bulk states and Dirac-type surface states. We also discuss the possibility that the bulk state could be a topological superconductor.

Organic Syntheses During the Impact of a Comet with a Gaseous Planet

1997 ◽  
Vol 161 ◽  
pp. 189-195
Author(s):  
Cesare Guaita ◽  
Roberto Crippa ◽  
Federico Manzini
Keyword(s):  
Polymeric Material ◽  
Molecular Form ◽  
Parent Compound ◽  
Blue Filter ◽  
Organic Syntheses ◽  
The Impact

AbstractA large amount of CO has been detected above many SL9/Jupiter impacts. This gas was never detected before the collision. So, in our opinion, CO was released from a parent compound during the collision. We identify this compound as POM (polyoxymethylene), a formaldehyde (HCHO) polymer that, when suddenly heated, reformes monomeric HCHO. At temperatures higher than 1200°K HCHO cannot exist in molecular form and the most probable result of its decomposition is the formation of CO. At lower temperatures, HCHO can react with NH3 and/or HCN to form high UV-absorbing polymeric material. In our opinion, this kind of material has also to be taken in to account to explain the complex evolution of some SL9 impacts that we observed in CCD images taken with a blue filter.

Zero-loss omega-filtered REM and RHEED on the new Zeiss 912

1991 ◽  
Vol 49 ◽  
pp. 616-617
Author(s):  
J.C.H. Spence ◽  
J. Mayer
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Surface States ◽  
Ccd Camera ◽  
Dark Field ◽  
Ion Pump ◽  
Magnetic Imaging ◽  
Reflection Electron Microscopy ◽  
Diffraction Patterns ◽  
Large Background

The Zeiss 912 is a new fully digital, side-entry, 120 Kv TEM/STEM instrument for materials science, fitted with an omega magnetic imaging energy filter. Pumping is by turbopump and ion pump. The magnetic imaging filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient parallel (area) detection. The energy loss intensity distribution may also be displayed on the screen, and recorded by scanning it over the PMT supplied. If a CCD camera is fitted and suitable new software developed, “parallel ELS” recording results. For large fields of view, filtered images can be recorded much more efficiently than by Scanning Reflection Electron Microscopy, and the large background of inelastic scattering removed. We have therefore evaluated the 912 for REM and RHEED applications. Causes of streaking and resonance in RHEED patterns are being studied, and a more quantitative analysis of CBRED patterns may be possible. Dark field band-gap REM imaging of surface states may also be possible.

Sign in / Sign up

Export Citation Format

Share Document