EXCHANGE FIELD EFFECT ON THE ANDREEV BOUND STATE STUDIED BY FERROMAGNET/HIGH Tc SUPERCONDUCTOR INTERFACE

2005 ◽  
Vol 19 (01n03) ◽  
pp. 495-497 ◽  
Author(s):  
K.-W. NG ◽  
MARIO FREAMAT
Keyword(s):  
Bound States ◽  
Bound State ◽  
Exchange Field ◽  
Zero Energy ◽  
S Wave ◽  
High Tc ◽  
Andreev Bound States ◽  
High Tc Superconductor ◽  
Energy Peak ◽  
Andreev Bound State

We have prepared Ag / BSCCO and Fe / Ag / BSCCO planar junctions to study the effect of Fe exchange field on the tunneling spectra. The junctions were constructed so that the tunneling direction is within the ab-plane, either along the maximum or minimum gap direction. Andreev bound states were observed as zero energy peak in the minimum gap direction. The exchange field caused major splitting of the zero energy peak, which did not occur in Ag / BSCCO junctions. We had detected a few percent (6 to 7%) of s-wave subcomponent at the interface in many of these junctions. This s-wave subcomponent had a Tc of about 20K.

scholarly journals Study on Nonmagnetic Impurities in the Superconducting State of Two-Dimensional t-J Model

1998 ◽  
Vol 12 (24) ◽  
pp. 2447-2454 ◽  
Author(s):  
Hideki Tanaka ◽  
Kazuhiro Kuboki ◽  
Manfred Sigrist
Keyword(s):  
Superconducting State ◽  
Mean Field ◽  
Bound State ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Zero Energy ◽  
S Wave ◽  
Localized State ◽  
Nonmagnetic Impurities ◽  
Andreev Bound State

We study the effect of nonmagnetic impurities in the superconducting state of the t–J model. The Bogoliubov de Gennes equation is derived using a slave-boson mean-field approximation, and we solve it numerically at T = 0. The dx2-y2-wave order parameter is suppressed near an impurity and the extended s-wave component is induced. We also find the local CDW-like feature due to the Friedel oscillations. This leads to the splitting of the expected zero-energy Andreev bound state. Therefore the system is unlikely introducing a localized state of other symmetry such as superconductivity with broken time reversal symmetry or antiferromagnetism.

QUANTUM DISSIPATION DUE TO THE ZERO ENERGY BOUND STATES IN HIGH-TC SUPERCONDUCTOR JUNCTIONS

2008 ◽  
Author(s):  
S. KAWABATA ◽  
S. KASHIWAYA ◽  
Y. ASANO ◽  
Y. TANAKA ◽  
T. KATO ◽  
...  
Keyword(s):  
Bound States ◽  
Quantum Dissipation ◽  
Zero Energy ◽  
High Tc ◽  
High Tc Superconductor ◽  
Energy Bound

scholarly journals Fundamental dissipation due to bound fermions in the zero-temperature limit

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Autti ◽  
S. L. Ahlstrom ◽  
R. P. Haley ◽  
A. Jennings ◽  
G. R. Pickett ◽  
...  
Keyword(s):  
Critical Velocity ◽  
Ground State ◽  
Bound States ◽  
Bound State ◽  
Temperature Limit ◽  
Pair Breaking ◽  
Zero Temperature ◽  
Andreev Bound States ◽  
Macroscopic Object

Abstract The ground state of a fermionic condensate is well protected against perturbations in the presence of an isotropic gap. Regions of gap suppression, surfaces and vortex cores which host Andreev-bound states, seemingly lift that strict protection. Here we show that in superfluid 3He the role of bound states is more subtle: when a macroscopic object moves in the superfluid at velocities exceeding the Landau critical velocity, little to no bulk pair breaking takes place, while the damping observed originates from the bound states covering the moving object. We identify two separate timescales that govern the bound state dynamics, one of them much longer than theoretically anticipated, and show that the bound states do not interact with bulk excitations.

ANDREEV SPECTRUM AND SUPERCURRENT IN A DOUBLE FERROMAGNET CLEAN JOSEPHSON JUNCTION

2007 ◽  
Vol 21 (09) ◽  
pp. 505-529 ◽  
Author(s):  
V. PALTOGLOU ◽  
I. MARGARIS ◽  
N. FLYTZANIS
Keyword(s):  
Energy Spectrum ◽  
Bound States ◽  
Reasonable Agreement ◽  
Double Resonance ◽  
Exchange Field ◽  
Extensive Investigation ◽  
Andreev Bound States ◽  
Weak Exchange ◽  
Interface Potential ◽  
Analytical Formulas

We consider a superconductor/double-ferromagnet/superconductor (S/I1/F/IC/F'/I2/S) ballistic junction with thin insulating layers in the interfaces. An extensive investigation is carried out for the possibility of 0- or π-junction and the important phaseshift. The average exchange field for the two ferromagnets has limited use, only for weak exchange fields. Several analytical formulas are obtained for the energy spectrum in simple cases with interface potential (a) absent, (b) between ferromagnets only, (c) double resonance barrier between S and F layers. They give reasonable agreement even outside their range of validity. For the case of strong S/F barriers we find a strong interplay of Andreev bound states and interbarrier resonances.

scholarly journals ELECTRONIC BOUND STATES IN PARITY-PRESERVING QED3 APPLIED TO HIGH-Tc CUPRATE SUPERCONDUCTORS

2003 ◽  
Vol 18 (05) ◽  
pp. 725-741 ◽  
Author(s):  
H. R. CHRISTIANSEN ◽  
O. M. DEL CIMA ◽  
M. M. FERREIRA ◽  
J. A. HELAYËL-NETO
Keyword(s):  
Bound States ◽  
Cuprate Superconductors ◽  
Energy Scale ◽  
Spontaneous Breaking ◽  
Electron Interaction ◽  
Oxide Superconductors ◽  
S Wave ◽  
High Tc ◽  
Pair Condensation ◽  
Copper Oxide Superconductors

We consider a parity-preserving QED 3 model with spontaneous breaking of the gauge symmetry as a framework for the evaluation of the electron–electron interaction potential underlying high-T c superconductivity. The fact that the resulting potential, -CsK0(Mr), is non-confining and "weak" (in the sense of Kato) strongly suggests the mechanism of pair-condensation. This potential, compatible with an s-wave order parameter, is then applied to the Schrödinger equation for the sake of numerical calculations, thereby enforcing the existence of bound states. The results worked out by means of our theoretical framework are checked by considering a number of phenomenological data extracted from different copper oxide superconductors. The agreement may motivate a deeper analysis of our model viewing an application to quasiplanar cuprate superconductors. The data analyzed here suggest an energy scale of 1–10 meV for the breaking of the U(1)-symmetry.

scholarly journals Andreev bound states, surfaces and subdominant pairing in high Tc superconductors

1998 ◽  
Vol 59 (10-12) ◽  
pp. 2040-2044 ◽  
Author(s):  
D. Rainer ◽  
H. Burkhardt ◽  
M. Fogelström ◽  
J.A. Sauls
Keyword(s):  
Bound States ◽  
High Tc Superconductors ◽  
High Tc ◽  
Andreev Bound States

scholarly journals Spatial Rabi oscillations between Majorana bound states and quantum dots

2018 ◽  
Vol 9 ◽  
pp. 1527-1535
Author(s):  
Jun-Hui Zheng ◽  
Dao-Xin Yao ◽  
Zhi Wang
Keyword(s):  
Quantum Dot ◽  
Bound States ◽  
Bound State ◽  
Double Quantum ◽  
Energy Splitting ◽  
Rabi Oscillations ◽  
Andreev Bound States ◽  
Majorana Bound States ◽  
Nonlocal Quantum ◽  
Equal Amplitude

Background: A Majorana bound state is a superconducting quasiparticle that is the superposition of particle and hole with equal amplitude. We propose a verification of this amplitude equality by analyzing the spatial Rabi oscillations of the quantum states of a quantum dot that is tunneling-coupled to the Majorana bound states. Results: We find two resonant Rabi driving energies that correspond to the energy splitting due to the coupling of two spatially separated Majorana bound states. The resulting Rabi oscillating frequencies from these two different resonant driving energies are identical for the Majorana bound states, while different for ordinary Andreev bound states. We further study a double-quantum-dot setup and find a nonlocal quantum correlation between them that is mediated by two Majorana bound states. This nonlocal correlation has the signature of additional resonant driving energies. Conclusion: Our method can be used to distinguish between Majorana bound states and Andreev bound states. It also gives a precise measurement of the energy splitting between two Majorana bound states.

scholarly journals Zero-energy Andreev bound states from quantum dots in proximitized Rashba nanowires

2018 ◽  
Vol 98 (24) ◽  
Author(s):  
Christopher Reeg ◽  
Olesia Dmytruk ◽  
Denis Chevallier ◽  
Daniel Loss ◽  
Jelena Klinovaja
Keyword(s):  
Quantum Dots ◽  
Bound States ◽  
Zero Energy ◽  
Andreev Bound States
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