Analytic dynamics of the one-dimensional tight-binding model: II. Bloch electrons in a rational magnetic field

1988 ◽  
Vol 21 (28) ◽  
pp. 4967-4978 ◽  
Author(s):  
S W Lovesey
2019 ◽  
Vol 6 (5) ◽  
Author(s):  
Fernando de Juan ◽  
Jens H Bardarson ◽  
Roni Ilan

Among the different platforms to engineer Majorana fermions in one-dimensional topological superconductors, topological insulator nanowires remain a promising option. Threading an odd number of flux quanta through these wires induces an odd number of surface channels, which can then be gapped with proximity induced pairing. Because of the flux and depending on energetics, the phase of this surface pairing may or may not wind around the wire in the form of a vortex. Here we show that for wires with discrete rotational symmetry, this vortex is necessary to produce a fully gapped topological superconductor with localized Majorana end states. Without a vortex the proximitized wire remains gapless, and it is only if the symmetry is broken by disorder that a gap develops, which is much smaller than the one obtained with a vortex. These results are explained with the help of a continuum model and validated numerically with a tight binding model, and highlight the benefit of a vortex for reliable use of Majorana fermions in this platform.


1997 ◽  
Vol 11 (24) ◽  
pp. 2941-2960
Author(s):  
Kazumoto Iguchi

We study semiconductivity of protein with a primary structure, where we use the transfer matrix method of the tight-binding model for electrons in a protein. We first introduce the model and the scheme for obtaining the spectrum. Second, we set up the transfer matrices in order to apply for a protein with an amino acid sequence. Third, we prove the Saxon–Hutner conjecture for the one-dimensional disordered polyatomic chains, and apply it to the protein system. We show that this theorem provides a good foundation for understanding the intriguing semiconductive character of the protein, which was first suggested by Szent–Györgyi a long time ago.


2014 ◽  
Vol 90 (12) ◽  
Author(s):  
H. Javan Mard ◽  
José A. Hoyos ◽  
E. Miranda ◽  
V. Dobrosavljević

AIP Advances ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 015127
Author(s):  
Qiuyuan Chen ◽  
Jiawei Chang ◽  
Lin Ma ◽  
Chenghan Li ◽  
Liangfei Duan ◽  
...  

1996 ◽  
Vol 10 (28) ◽  
pp. 3827-3856 ◽  
Author(s):  
KAZUMOTO IGUCHI

A tight-binding model is formulated for the calculation of the electronic structure and the ground state energy of the quantum ladder under a magnetic field, where the magnetic flux at the nth plaquette is given by ϕn. First, the theory is applied to obtain the electronic spectra of the quantum ladder models with particular magnetic fluxes such as uniform magnetic fluxes, ϕn=0 and 1/2, and the staggered magnetic flux, ϕn= (−1)n+1ϕ0. From these, it is found that as the effect of electron hopping between two chains—the anisotropy parameter r=ty/tx—is increased, there are a metal-semimetal transition at r=0 and a semimetal–semiconductor transition at r=2 in the first case, and metal-semiconductor transitions at r=0 in the second and third cases. These transitions are thought of as a new category of metal-insulator transition due to the hopping anisotropy of the system. Second, using the spectrum, the ground state energy is calculated in terms of the parameter r. It is found that the ground state energy in the first case diverges as r becomes arbitrarily large, while that in the second and third cases can have the single or double well structure with respect to r, where the system is stable at some critical value of r=rc and the transition between the single and double well structures is associated with whether tx is less than a critical value of txc. The latter cases are very reminiscent of physics in polyacetylene studied by Su, Schrieffer and Heeger.


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