scholarly journals Evidence for orbital order and its relation to superconductivity in FeSe0.4Te0.6

2015 ◽  
Vol 1 (9) ◽  
pp. e1500206 ◽  
Author(s):  
Udai R. Singh ◽  
Seth C. White ◽  
Stefan Schmaus ◽  
Vladimir Tsurkan ◽  
Alois Loidl ◽  
...  
Keyword(s):  
Structural Phase ◽  
Tight Binding ◽  
Electronic States ◽  
Orbital Ordering ◽  
Binding Model ◽  
Quasi Particle ◽  
Iron Based Superconductors ◽  
Iron Chalcogenide ◽  
Correlated Electron ◽  
Iron Based

The emergence of nematic electronic states accompanied by a structural phase transition is a recurring theme in many correlated electron materials, including the high-temperature copper oxide– and iron-based superconductors. We provide evidence for nematic electronic states in the iron-chalcogenide superconductor FeSe0.4Te0.6 from quasi-particle scattering detected in spectroscopic maps. The symmetry-breaking states persist above Tc into the normal state. We interpret the scattering patterns by comparison with quasi-particle interference patterns obtained from a tight-binding model, accounting for orbital ordering. The relation to superconductivity and the influence on the coherence length are discussed.

scholarly journals Scalable Majorana vortex modes in iron-based superconductors

2020 ◽  
Vol 6 (9) ◽  
pp. eaay0443 ◽  
Author(s):  
Ching-Kai Chiu ◽  
T. Machida ◽  
Yingyi Huang ◽  
T. Hanaguri ◽  
Fu-Chun Zhang
Keyword(s):  
Tight Binding ◽  
Three Dimensional ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Zero Energy ◽  
Binding Model ◽  
Zero Bias ◽  
Iron Based Superconductors ◽  
Iron Based ◽  
Important Indication

The iron-based superconductor FeTexSe1−x is one of the material candidates hosting Majorana vortex modes residing in the vortex cores. It has been observed by recent scanning tunneling spectroscopy measurement that the fraction of vortex cores having zero-bias peaks decreases with increasing magnetic field on the surface of FeTexSe1−x. The hybridization of two Majorana vortex modes cannot simply explain this phenomenon. We construct a three-dimensional tight-binding model simulating the physics of over a hundred Majorana vortex modes in FeTexSe1−x. Our simulation shows that the Majorana hybridization and disordered vortex distribution can explain the decreasing fraction of the zero-bias peaks observed in the experiment; the statistics of the energy peaks off zero energy in our Majorana simulation are in agreement with the experiment. These agreements lead to an important indication of scalable Majorana vortex modes in FeTexSe1−x. Thus, FeTexSe1−x can be one promising platform having scalable Majorana qubits for quantum computing.

Hybridization in Electronic States and Optical Properties of Covalent Amorphous Semiconductors

1999 ◽  
Vol 588 ◽  
Author(s):  
Yuzo Shinozuka
Keyword(s):  
Optical Properties ◽  
Spatial Correlation ◽  
Nearest Neighbor ◽  
Tight Binding ◽  
Electronic States ◽  
Amorphous Semiconductors ◽  
Transfer Energy ◽  
Binding Model ◽  
Covalent Bonds ◽  
Conduction Bands

AbstractThe electronic structure and optical properties of covalent amorphous semiconductors are theoretically studied with special attention to the s-p hybridization in electronic states and the spatial correlation in their mixing. One-dimensional tight binding model is used in which the interatomic transfer energy of an electron between nearest neighbor atoms depends linearly on their interatomic distance. All the electronic states are numerically calculated for a 150-atom system and the ensemble average is taken over 10 samples. Following results have been obtained. As the degree of randomness increases, the degree of hybridization decreases and rearrangements in the covalent bonds take place. The width of the band gap decreases but the gap remains rather long compared to a case where the spatial correlation is neglected. There appears a characteristic peak in the optical absorption spectrum, which reflects central peaks in the partial (s- or p-) density of states in the valence and conduction bands and is related to an electron localization caused by the spatial correlation.

Electronic States of BCN Alloy Nanotubes in a Simple Tight-Binding Model

2003 ◽  
Vol 72 (10) ◽  
pp. 2656-2664 ◽  
Author(s):  
Tomoaki Yoshioka ◽  
Hidekatsu Suzuura ◽  
Tsuneya Ando
Keyword(s):  
Tight Binding ◽  
Electronic States ◽  
Tight Binding Model ◽  
Binding Model

scholarly journals Tight-binding models for the iron-based superconductors

2009 ◽  
Vol 80 (10) ◽  
Author(s):  
Helmut Eschrig ◽  
Klaus Koepernik
Keyword(s):  
Tight Binding ◽  
Iron Based Superconductors ◽  
Binding Models ◽  
Iron Based
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