scholarly journals Signatures of Majorana fermions in topological insulator Josephson junction devices

2014 ◽  
Vol 89 (7) ◽  
Author(s):  
Benjamin J. Wieder ◽  
Fan Zhang ◽  
C. L. Kane
Keyword(s):  
Josephson Junction ◽  
Topological Insulator ◽  
Majorana Fermions

scholarly journals Revealing the interference effect of Majorana fermions in a topological Josephson junction

2018 ◽  
Vol 9 ◽  
pp. 520-529 ◽  
Author(s):  
Jie Liu ◽  
Tiantian Yu ◽  
Juntao Song
Keyword(s):  
Josephson Junction ◽  
Interference Effect ◽  
Josephson Effect ◽  
Andreev Reflection ◽  
Local Density ◽  
Localized States ◽  
Majorana Fermions ◽  
Local Density Of States ◽  
Single Side ◽  
Period Oscillation

We study theoretically the local density of states (DOS) in a topological Josephson junction. We show that the well-known 4π Josephson effect originates from the interference effect between two Majorana fermions (MFs) that are localized at the Josephson junction. In addition, the DOS for electrons (holes) shows the 4π interference information along each parity conserved energy spectrum. The DOS displays a 2π period oscillation when two trivial states interfere with each other. This means that the DOS information may be used to distinguish the MFs from trivial localized states. We suggest that the interference effect and the DOS can be detected by using two STM leads or two normal leads. A single side lead can only detect the Andreev reflection tunneling process in the junction, which cannot reveal information about the interference effect in general. However, using two side leads, we can reveal information about the interference effect of the MFs as well as the DOS by combining Andreev reflection with the electron transmission process.

scholarly journals Studies on the origin of the interfacial superconductivity of Sb2Te3/Fe1+yTe heterostructures

2019 ◽  
Vol 117 (1) ◽  
pp. 221-227 ◽  
Author(s):  
Jing Liang ◽  
Yu Jun Zhang ◽  
Xiong Yao ◽  
Hui Li ◽  
Zi-Xiang Li ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Topological Insulator ◽  
Surface States ◽  
The Other ◽  
Majorana Fermions ◽  
Bulk Conductivity ◽  
Indirect Coupling ◽  
Topological Surface ◽  
Excess Fe

The recent discovery of the interfacial superconductivity (SC) of the Bi2Te3/Fe1+yTe heterostructure has attracted extensive studies due to its potential as a novel platform for trapping and controlling Majorana fermions. Here we present studies of another topological insulator (TI)/Fe1+yTe heterostructure, Sb2Te3/Fe1+yTe, which also has an interfacial 2-dimensional SC. The results of transport measurements support that reduction of the excess Fe concentration of the Fe1+yTe layer not only increases the fluctuation of its antiferromagnetic (AFM) order but also enhances the quality of the SC of this heterostructure system. On the other hand, the interfacial SC of this heterostructure was found to have a wider-ranging TI-layer thickness dependence than that of the Bi2Te3/Fe1+yTe heterostructure, which is believed to be attributed to the much higher bulk conductivity of Sb2Te3that enhances indirect coupling between its top and bottom topological surface states (TSSs). Our results provide evidence of the interplay among the AFM order, itinerant carries from the TSSs, and the induced interfacial SC of the TI/Fe1+yTe heterostructure system.

Observation of a.c. Josephson effect in gate tunable Josephson junction on topological insulator (Bi0.2Sb0.8)2 Te3 films

2019 ◽  
Author(s):  
Yuusuke Takeshige ◽  
Sadashige Matsuo ◽  
Russell Stewart Deacon ◽  
Kento Ueda ◽  
Yosuke Sato ◽  
...  
Keyword(s):  
Josephson Junction ◽  
Topological Insulator ◽  
Josephson Effect

scholarly journals Conditions for fully gapped topological superconductivity in topological insulator nanowires

2019 ◽  
Vol 6 (5) ◽  
Author(s):  
Fernando de Juan ◽  
Jens H Bardarson ◽  
Roni Ilan
Keyword(s):  
Topological Insulator ◽  
Continuum Model ◽  
Rotational Symmetry ◽  
Tight Binding ◽  
Majorana Fermions ◽  
Tight Binding Model ◽  
Binding Model ◽  
One Dimensional ◽  
Topological Superconductors ◽  
The One

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.

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