scholarly journals Controllable Majorana fermions on domain walls of a magnetic topological insulator

2018 ◽  
Vol 98 (2) ◽  
Author(s):  
Jing Wang
Keyword(s):  
Topological Insulator ◽  
Domain Walls ◽  
Majorana Fermions

scholarly journals Controllable quantum point junction on the surface of an antiferromagnetic topological insulator

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicodemos Varnava ◽  
Justin H. Wilson ◽  
J. H. Pixley ◽  
David Vanderbilt
Keyword(s):  
Topological Insulator ◽  
Information Science ◽  
Domain Walls ◽  
Quantum Hall ◽  
Edge State ◽  
Wave Functions ◽  
Quantum Hall Systems ◽  
Electron Quantum ◽  
Quantum Point ◽  
Higher Temperature

AbstractEngineering and manipulation of unidirectional channels has been achieved in quantum Hall systems, leading to the construction of electron interferometers and proposals for low-power electronics and quantum information science applications. However, to fully control the mixing and interference of edge-state wave functions, one needs stable and tunable junctions. Encouraged by recent material candidates, here we propose to achieve this using an antiferromagnetic topological insulator that supports two distinct types of gapless unidirectional channels, one from antiferromagnetic domain walls and the other from single-height steps. Their distinct geometric nature allows them to intersect robustly to form quantum point junctions, which then enables their control by magnetic and electrostatic local probes. We show how the existence of stable and tunable junctions, the intrinsic magnetism and the potential for higher-temperature performance make antiferromagnetic topological insulators a promising platform for electron quantum optics and microelectronic applications.

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.

scholarly journals Evidence for dispersing 1D Majorana channels in an iron-based superconductor

Science ◽  
2020 ◽  
Vol 367 (6473) ◽  
pp. 104-108 ◽  
Author(s):  
Zhenyu Wang ◽  
Jorge Olivares Rodriguez ◽  
Lin Jiao ◽  
Sean Howard ◽  
Martin Graham ◽  
...  
Keyword(s):  
Bound States ◽  
Domain Walls ◽  
Lattice Structure ◽  
Condensed Matter ◽  
One Dimension ◽  
Scanning Tunneling ◽  
Majorana Fermions ◽  
Topological Phase ◽  
Linear Dispersion ◽  
Combined Data

The possible realization of Majorana fermions as quasiparticle excitations in condensed-matter physics has created much excitement. Most studies have focused on Majorana bound states; however, propagating Majorana states with linear dispersion have also been predicted. Here, we report scanning tunneling spectroscopic measurements of crystalline domain walls (DWs) in FeSe0.45Te0.55. We located DWs across which the lattice structure shifts by half a unit cell. These DWs have a finite, flat density of states inside the superconducting gap, which is a hallmark of linearly dispersing modes in one dimension. This signature is absent in DWs in the related superconductor, FeSe, which is not in the topological phase. Our combined data are consistent with the observation of dispersing Majorana states at a π-phase shift DW in a proximitized topological material.

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.

scholarly journals Quantized chiral edge conduction on domain walls of a magnetic topological insulator

Science ◽  
2017 ◽  
Vol 358 (6368) ◽  
pp. 1311-1314 ◽  
Author(s):  
K. Yasuda ◽  
M. Mogi ◽  
R. Yoshimi ◽  
A. Tsukazaki ◽  
K. S. Takahashi ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Domain Walls
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