scholarly journals Superconducting gap and pseudogap in the surface states of the iron-based superconductor PrFeAsO1−y studied by angle-resolved photoemission spectroscopy

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
K. Hagiwara ◽  
M. Ishikado ◽  
M. Horio ◽  
K. Koshiishi ◽  
S. Nakata ◽  
...  
Keyword(s):  
Surface States ◽  
Photoemission Spectroscopy ◽  
Superconducting Gap ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Iron Based

scholarly journals Revealing the intrinsic superconducting gap anisotropy in surface-neutralized BaFe2(As0.7P0.3)2

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ziming Xin ◽  
Yudi Wang ◽  
Cong Cai ◽  
Zhengguo Wang ◽  
Lei Chen ◽  
...  
Keyword(s):  
Alkaline Earth ◽  
Theoretical Models ◽  
Photoemission Spectroscopy ◽  
Superconducting Gap ◽  
Iron Based Superconductors ◽  
Future Studies ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Gap Anisotropy ◽  
Iron Based ◽  
Potassium Deposition

AbstractAlkaline-earth iron arsenide (122) is one of the most studied families of iron-based superconductors, especially for angle-resolved photoemission spectroscopy. While extensive photoemission results have been obtained, the surface complexity of 122 caused by its charge-non-neutral surface is rarely considered. Here, we show that the surface of 122 can be neutralized by potassium deposition. In potassium-coated BaFe2(As0.7P0.3)2, the surface-induced spectral broadening is strongly suppressed, and hence the coherent spectra that reflect the intrinsic bulk electronic state recover. This enables the measuring of superconducting gap with unpreceded precision. The result shows the existence of two pairing channels. While the gap anisotropy on the outer hole/electron pockets can be well fitted using an s± gap function, the gap anisotropy on the inner hole/electron shows a clear deviation. Our results provide quantitative constraints for refining theoretical models and also demonstrate an experimental method for revealing the intrinsic electronic properties of 122 in future studies.

scholarly journals Three-dimensional superconducting gap in FeSe from angle-resolved photoemission spectroscopy

2018 ◽  
Vol 97 (18) ◽  
Author(s):  
Y. S. Kushnirenko ◽  
A. V. Fedorov ◽  
E. Haubold ◽  
S. Thirupathaiah ◽  
T. Wolf ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Photoemission Spectroscopy ◽  
Superconducting Gap ◽  
Angle Resolved Photoemission Spectroscopy

Sodium Doping of Bi/Si(111) Ultra-Thin Films

2014 ◽  
Vol 213 ◽  
pp. 65-70
Author(s):  
Maria V. Ryzhkova ◽  
Dimitry V. Gruznev ◽  
Elena A. Borisenko ◽  
Dmitry A. Tsukanov
Keyword(s):  
Thin Films ◽  
Electrical Conductance ◽  
Surface States ◽  
Surface Conductivity ◽  
Metallic Surface ◽  
Photoemission Spectroscopy ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Sodium Doping ◽  
Reconstructed Surfaces ◽  
Conductance Changes

Changes in electrical conductance of the Bi/Si (111) reconstructed surfaces and Bi {012} or Bi (001) ultra-thin films have been studied after sodium deposition at room temperature. It was observed that deposition of sodium onto Si (111)-β-3×3-Bi surface results in increasing of surface conductivity up to 0.3 monolayers (ML) of adsorbed sodium atoms. These conductance changes were explained by developing of the metallic surface states in the band gap as revealed by angle resolved photoemission spectroscopy spectra. Moreover, it was shown that sodium adsorption onto Bi {012} and Bi (001) thin films leads to drastic changes in its surface conductivity including a peak of maximum electrical conductance at 0.5 monolayers of adsorbed sodium.

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.

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