scholarly journals Electronic structure of a mesoscopic superconducting disk: Quasiparticle tunneling between the giant vortex core and the disk edge

2019 ◽  
Vol 99 (13) ◽  
Author(s):  
A. V. Samokhvalov ◽  
I. A. Shereshevskii ◽  
N. K. Vdovicheva ◽  
M. Taupin ◽  
I. M. Khaymovich ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Vortex Core ◽  
Quasiparticle Tunneling ◽  
Giant Vortex

Electronic structure around a vortex core in iron pnictide superconductors

2010 ◽  
Vol 82 (18) ◽  
Author(s):  
Da Wang ◽  
Jian Xu ◽  
Yuan-Yuan Xiang ◽  
Qiang-Hua Wang
Keyword(s):  
Electronic Structure ◽  
Vortex Core ◽  
Iron Pnictide ◽  
Pnictide Superconductors

VORTEX STATE IN f-WAVE SUPERCONDUCTORS

2007 ◽  
Vol 21 (17) ◽  
pp. 1051-1056
Author(s):  
QIANG HAN
Keyword(s):  
Electronic Structure ◽  
Cobalt Oxide ◽  
Triangular Lattice ◽  
Vortex Core ◽  
Bound States ◽  
Vortex State ◽  
Pairing Symmetry ◽  
Effective Hamiltonian ◽  
F Wave

Motivated by the controversy concerning the pairing symmetry of the superconducting sodium-doped cobalt oxide, we investigate the microscopic electronic structure of an f-wave superconductor in the vortex state by diagonalizing an effective Hamiltonian specified in the triangular lattice self-consistently. We find that the low-lying vortex core states are in essence extended for the nodal f-wave superconductors. In comparison, we find localized bound states in the vortex core of the fully-gapped (d + id')-wave superconductors.

Charging Effects of Vortex Core in High Temperature Superconductors Probed by Nuclear Quadrupole Interaction

2002 ◽  
Vol 57 (6-7) ◽  
pp. 488-494 ◽  
Author(s):  
Ken-ichi Kumagai ◽  
Kosuke Kakuyanagi ◽  
Koji Nozaki ◽  
Yuji Matsuda
Keyword(s):  
Electronic Structure ◽  
High Temperature ◽  
High Resolution ◽  
Vortex Core ◽  
High Temperature Superconductors ◽  
Nuclear Quadrupole Interaction ◽  
Bcs Theory ◽  
The Novel ◽  
Nuclear Quadrupole ◽  
Positively Charged

From high resolution measurements of the nuclear quadrupole frequencies we obtain experimental evidence that a vortex in high Tc superconductors (HTSC) traps a finite electric charge. In slightly overdoped YBa2Cu3O7 the vortex is negatively charged by trapping electrons, while in underdoped YBa2Cu4O8 it is positively charged by expelling electrons. The sign of the trapped charge is opposite to the sign predicted by the conventional BCS theory. Moreover, in both materials the deviation of the magnitude of the charge from the theory is significant. These features can be attributed to the novel electronic structure of the vortex in HTSC

EELS Measurement of the Local Electronic Structure of Copper Atoms Segregated to Aluminum Grain Boundaries

1996 ◽  
Vol 54 ◽  
pp. 342-343
Author(s):  
S.J. Splinter ◽  
J. Bruley ◽  
P.E. Batson ◽  
D.A. Smith ◽  
R. Rosenberg
Keyword(s):  
Electronic Structure ◽  
Grain Boundaries ◽  
Boundary Segregation ◽  
Thin Layers ◽  
Nominal Composition ◽  
Spatially Resolved ◽  
Service Lifetime ◽  
Heat Treated ◽  
Probe Size ◽  
Local Electronic Structure

It has long been known that the addition of Cu to Al interconnects improves the resistance to electromigration failure. It is generally accepted that this improvement is the result of Cu segregation to Al grain boundaries. The exact mechanism by which segregated Cu increases service lifetime is not understood, although it has been suggested that the formation of thin layers of θ-CuA12 (or some metastable substoichiometric precursor, θ’ or θ”) at the boundaries may be necessary. This paper reports measurements of the local electronic structure of Cu atoms segregated to Al grain boundaries using spatially resolved EELS in a UHV STEM. It is shown that segregated Cu exists in a chemical environment similar to that of Cu atoms in bulk θ-phase precipitates.Films of 100 nm thickness and nominal composition Al-2.5wt%Cu were deposited by sputtering from alloy targets onto NaCl substrates. The samples were solution heat treated at 748K for 30 min and aged at 523K for 4 h to promote equilibrium grain boundary segregation. EELS measurements were made using a Gatan 666 PEELS spectrometer interfaced to a VG HB501 STEM operating at 100 keV. The probe size was estimated to be 1 nm FWHM. Grain boundaries with the narrowest projected width were chosen for analysis. EDX measurements of Cu segregation were made using a VG HB603 STEM.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

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