scholarly journals Andreev bound states in superconductor/ferromagnet point contact Andreev reflection spectra

2017 ◽  
Vol 95 (9) ◽  
Author(s):  
K. A. Yates ◽  
L. A. B. Olde Olthof ◽  
M. E. Vickers ◽  
D. Prabhakaran ◽  
M. Egilmez ◽  
...  
Keyword(s):  
Bound States ◽  
Andreev Reflection ◽  
Point Contact ◽  
Reflection Spectra ◽  
Andreev Bound States

Absence of Andreev bound states inβ−PdBi2probed by point-contact Andreev reflection spectroscopy

2016 ◽  
Vol 94 (2) ◽  
Author(s):  
Liqiang Che ◽  
Tian Le ◽  
C. Q. Xu ◽  
X. Z. Xing ◽  
Zhixiang Shi ◽  
...  
Keyword(s):  
Bound States ◽  
Andreev Reflection ◽  
Point Contact ◽  
Reflection Spectroscopy ◽  
Andreev Bound States

Two-gap superconductivity in the Fe-1111 superconductor LaFeAsO1−x Fx: A point-contact Andreev-reflection study

Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
Renato Gonnelli ◽  
Mauro Tortello ◽  
Dario Daghero ◽  
Giovanni Ummarino ◽  
Valeri Stepanov ◽  
...  
Keyword(s):  
Low Temperature ◽  
Theoretical Analysis ◽  
Temperature Dependence ◽  
Andreev Reflection ◽  
Point Contact ◽  
Layered Superconductor ◽  
Reflection Spectra ◽  
Eliashberg Theory ◽  
Boson Coupling ◽  
The Rich

AbstractPoint-contact Andreev-reflection (PCAR) experiments were performed in the Fe-1111 layered superconductor LaFeAsO0.9F0.1 with resistive T con ∼ 27 K. The observation of two pairs of peaks in the low-temperature Andreev-reflection spectra clearly indicates the presence of two order parameters. The behavior of the two gaps as a function of temperature, obtained by fitting the conductance curves by means of the generalized two-band Blonder-Tinkham-Klapwijk model, shows some anomalies. A theoretical analysis performed within the two-band Eliashberg theory with a generic electron-boson coupling can reproduce the low-temperature value of the two gaps but generally fails in giving a satisfactory fit of their overall temperature dependence, indicating the rich and complex physics of these newly discovered superconductors.

Suppressed Andreev reflection and helical Andreev bound states in triplet superconductor three-dimensional topological insulator

2015 ◽  
Vol 29 (04) ◽  
pp. 1550018 ◽  
Author(s):  
M. Khezerlou ◽  
H. Goudarzi
Keyword(s):  
Topological Insulator ◽  
Bound States ◽  
Andreev Reflection ◽  
Chemical Potential ◽  
Three Dimensional ◽  
P Wave ◽  
Superconducting Gap ◽  
Tunneling Conductance ◽  
Andreev Bound States ◽  
Josephson Supercurrent

Effect of proximity-induced unconventional p-wave superconductivity in a three-dimensional topological insulator-based S/F/S structure on the Andreev bound states (ABSs) and Josephson supercurrent is studied. We investigate, in detail, the suppression of Andreev reflection and helical ABSs in the presence of three types of triplet superconducting gap. The magnetization of ferromagnetic section is perpendicular to the surface of junction. The influence of such features on the supercurrent flow on the surface of the topological insulator is studied. We carry out our goal by introducing a relevant form of Dirac spinors for gapless renormalized by chemical potential μ excitation states. Therefore, it enables us to consider the virtual Andreev process, simultaneously, and we propose to investigate it in a tunneling conductance junction. It is shown that the results obtained in this case are completely different from those in conventional superconductivity, as s- or d-waves, for example, the magnetization is found to decrease the gap for px and px+ipy case, whereas increase it for py order. Strongly suppressed Andreev reflection is demonstrated.

scholarly journals Effect of Transport-Induced Charge Inhomogeneity on Point-Contact Andreev Reflection Spectra at Ferromagnet–Superconductor Interfaces

2012 ◽  
Vol 81 (8) ◽  
pp. 084704 ◽  
Author(s):  
Ya-Fen Hsu ◽  
Tien-Wei Chiang ◽  
Guang-Yu Guo ◽  
Shang-Fan Lee ◽  
Jun-Jih Liang
Keyword(s):  
Andreev Reflection ◽  
Point Contact ◽  
Reflection Spectra ◽  
Induced Charge

scholarly journals Andreev reflection spectroscopy in transition metal oxides

2018 ◽  
Vol 376 (2125) ◽  
pp. 20150001
Author(s):  
Karen A. Yates ◽  
Lesley F. Cohen
Keyword(s):  
Transition Metal ◽  
Transition Metal Oxides ◽  
Bound States ◽  
Andreev Reflection ◽  
Transport Current ◽  
Reflection Spectroscopy ◽  
Theme Issue ◽  
Andreev Bound States ◽  
Current Spin Polarization

Here we review the literature concerning measurement of the Andreev reflection between a superconductor (S) and ferromagnet (F), with particular attention to the case where the ferromagnet is a transition metal oxide. We discuss the practicality of utilization of the current models for determination of the transport current spin polarization and examine the evidence for Andreev bound states. This article is part of the theme issue ‘Andreev bound states’.

scholarly journals Analysis of point-contact Andreev reflection spectra in spin polarization measurements

2004 ◽  
Vol 70 (5) ◽  
Author(s):  
G. T. Woods ◽  
R. J. Soulen ◽  
I. Mazin ◽  
B. Nadgorny ◽  
M. S. Osofsky ◽  
...  
Keyword(s):  
Spin Polarization ◽  
Andreev Reflection ◽  
Point Contact ◽  
Reflection Spectra ◽  
Polarization Measurements

Conductance features in point contact Andreev reflection spectra

2009 ◽  
Vol 21 (9) ◽  
pp. 095701 ◽  
Author(s):  
V Baltz ◽  
A D Naylor ◽  
K M Seemann ◽  
W Elder ◽  
S Sheen ◽  
...  
Keyword(s):  
Andreev Reflection ◽  
Point Contact ◽  
Reflection Spectra

scholarly journals Andreev bound states and their signatures

2018 ◽  
Vol 376 (2125) ◽  
pp. 20180140 ◽  
Author(s):  
J. A. Sauls
Keyword(s):  
State Formation ◽  
Quantum Coherence ◽  
Bound States ◽  
Andreev Reflection ◽  
Bound State ◽  
Unconventional Superconductivity ◽  
Excitation Energies ◽  
Andreev Bound States ◽  
Properties Of Superconductors ◽  
Andreev Scattering

Many of the properties of superconductors related to quantum coherence are revealed when the superconducting state is forced to vary in space in response to an external magnetic field, a proximity contact, an interface to a ferromagnet or to impurities embedded in the superconductor. Among the earliest examples is Andreev reflection of an electron into a retro-reflected hole at a normal-superconducting interface. In regions of strong inhomogeneity, multiple Andreev reflection leads to the formation of sub-gap states, Andreev bound states , with excitation energies below the superconducting gap. These states play a central role in our understanding of inhomogeneous superconductors. The discoveries of unconventional superconductivity in many classes of materials, advances in fabrication of superconducting/ferromagnetic hybrids and nanostructures for confining superfluid 3 He, combined with theoretical developments in topological quantum matter have dramatically expanded the significance of branch conversion scattering and Andreev bound state formation. This collection of articles highlights developments in inhomogeneous superconductivity, unconventional superconductivity and topological phases of superfluid 3 He, in which Andreev scattering and bound states underpin much of the physics of these systems. This article provides an introduction to the basic physics of Andreev scattering, bound-state formation and their signatures. The goal is both an introduction for interested readers who are not already experts in the field, and to highlight examples in which branch conversion scattering and Andreev bound states provide unique signatures in the transport properties of superconductors. This article is part of the theme issue ‘Andreev bound states’.

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