Stochastic resonances and the mobility edge in a three-dimensional tight-binding Anderson model

1994 ◽  
Vol 50 (7) ◽  
pp. 4867-4870 ◽  
Author(s):  
Indra Dasgupta ◽  
Tanusri Saha ◽  
Abhijit Mookerjee
Keyword(s):  
Anderson Model ◽  
Tight Binding ◽  
Three Dimensional ◽  
Mobility Edge

Mobility edge in the three dimensional Anderson model

1985 ◽  
Vol 60 (1) ◽  
pp. 13-17 ◽  
Author(s):  
B. R. Buŀka ◽  
B. Kramer ◽  
A. MacKinnon
Keyword(s):  
Anderson Model ◽  
Three Dimensional ◽  
Mobility Edge

scholarly journals Cobalt-based magnetic Weyl semimetals with high-thermodynamic stabilities

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Wei Luo ◽  
Yuma Nakamura ◽  
Jinseon Park ◽  
Mina Yoon
Keyword(s):  
Tight Binding ◽  
Three Dimensional ◽  
Interlayer Coupling ◽  
First Principles Calculation ◽  
Optimization Approach ◽  
Binding Model ◽  
Nodal Lines ◽  
Weyl Semimetal ◽  
Topological Quantum ◽  
First Time

AbstractRecent experiments identified Co3Sn2S2 as the first magnetic Weyl semimetal (MWSM). Using first-principles calculation with a global optimization approach, we explore the structural stabilities and topological electronic properties of cobalt (Co)-based shandite and alloys, Co3MM’X2 (M/M’ = Ge, Sn, Pb, X = S, Se, Te), and identify stable structures with different Weyl phases. Using a tight-binding model, for the first time, we reveal that the physical origin of the nodal lines of a Co-based shandite structure is the interlayer coupling between Co atoms in different Kagome layers, while the number of Weyl points and their types are mainly governed by the interaction between Co and the metal atoms, Sn, Ge, and Pb. The Co3SnPbS2 alloy exhibits two distinguished topological phases, depending on the relative positions of the Sn and Pb atoms: a three-dimensional quantum anomalous Hall metal, and a MWSM phase with anomalous Hall conductivity (~1290 Ω−1 cm−1) that is larger than that of Co2Sn2S2. Our work reveals the physical mechanism of the origination of Weyl fermions in Co-based shandite structures and proposes topological quantum states with high thermal stability.

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.

Collective mode dispersions of organic chain compounds

Open Physics ◽  
2010 ◽  
Vol 8 (3) ◽  
Author(s):  
Željana Lošić ◽  
Paško Županović
Keyword(s):  
Collective Mode ◽  
Random Phase ◽  
Tight Binding ◽  
Three Dimensional ◽  
Plasmon Mode ◽  
Optical Data ◽  
Electron Interaction ◽  
Coulomb Interactions ◽  
One Dimensional ◽  
Donor And Acceptor

AbstractWe investigate the collective mode dispersions for the tight-binding dielectric matrix with two one-dimensional electron bands per donor and acceptor chains, and the three-dimensional long-range Coulomb electron-electron interaction within the random phase approximation. The hybridized collective modes are the result of the strong coupling between the intraband plasmon and the interband dipolar modes due to strong dipole Coulomb interactions. Our calculations show the existence of the low-energy renormalized plasmon mode above the electron-hole quasi-continuum in the long wavelength limit. The obtained modes are brought into correspondence with the optical data of quasi-one-dimensional organic conductor tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ). Namely, the renormalized plasmon and the dipolar mode are assigned to the observed excitations at respective energy scales of roughly 10 meV and 0.75 eV, explaining why lower excitation is eliminated while higher excitation persists below the temperature of the Peierls phase transition.

scholarly journals Unravelling the structure of the pneumococcal autolytic lysozyme

2005 ◽  
Vol 391 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Begoña Monterroso ◽  
Consuelo López-Zumel ◽  
José L. García ◽  
José L. Sáiz ◽  
Pedro García ◽  
...  
Keyword(s):  
Homology Modelling ◽  
Tight Binding ◽  
Three Dimensional ◽  
Divergent Evolution ◽  
Glycosyl Hydrolases ◽  
Three Dimensional Model ◽  
Lytic Enzymes ◽  
C Terminus ◽  
Global Fold ◽  
Positively Charged

The LytC lysozyme of Streptococcus pneumoniae forms part of the autolytic system of this important pathogen. This enzyme is composed of a C-terminal CM (catalytic module), belonging to the GH25 family of glycosyl hydrolases, and an N-terminal CBM (choline-binding module), made of eleven homologous repeats, that specifically recognizes the choline residues that are present in pneumococcal teichoic and lipoteichoic acids. This arrangement inverts the general assembly pattern of the major pneumococcal autolysin, LytA, and the lytic enzymes encoded by pneumococcal bacteriophages that place the CBM (made of six repeats) at the C-terminus. In the present paper, a three-dimensional model of LytC built by homology modelling of each module and consistent with spectroscopic and hydrodynamic studies is shown. In addition, the putative catalytic-pair residues are identified. Despite the inversion in the modular arrangement, LytC and the bacteriophage-encoded Cpl-1 lysozyme most probably adopt a similar global fold. However, the distinct choline-binding ability and their substrate-binding surfaces may reflect a divergent evolution directed by the different roles played by them in the host (LytC) or in the bacteriophage (Cpl-1). The tight binding of LytC to the pneumococcal envelope, mediated by the acquisition of additional choline-binding repeats, could facilitate the regulation of the potentially suicidal activity of this autolysin. In contrast, a looser attachment of Cpl-1 to the cell wall and the establishment of more favourable interactions between its highly negatively charged catalytic surface and the positively charged chains of pneumococcal murein could enhance the lytic activity of the parasite-encoded enzyme and therefore liberation of the phage progeny.

scholarly journals Three-dimensional Anderson model of localization with binary random potential

2003 ◽  
Vol 68 (6) ◽  
Author(s):  
I. V. Plyushchay ◽  
R. A. Römer ◽  
M. Schreiber
Keyword(s):  
Anderson Model ◽  
Random Potential ◽  
Three Dimensional
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