Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 18 of 18 for “"Andreev reflection"”.
-
Point-contact Andreev reflection studies on superconductors
Point-contact Andreev reflection spectroscopy (PCARS) and planar tunneling spectroscopy are used to investigate the density of states and superconducting gap structure of several novel superconducting systems. Theoretical and experimental background is given with an emphasis on PCARS as applied to …
-
Investigations of Crossed Andreev Reflection in Hybrid Superconductor-Ferromagnet Structures
… for signatures of this process, called crossed Andreev reflection (CAR), in three device geometries. The first devices studied are lateral spin valves. In these structures, when electrons with energies less than the superconducting energy gap are injected from one ferromagnetic wire into the …
-
The study of weak ferromagnetism by andreev reflection spin spectroscopy and development of bimorph electro-thermal actuators
… efficiency of spintronic devices. Point contact Andreev reflection (PCAR) spectroscopy, one of the most popular and reliable techniques, was used to obtain the conductance and by analyzing them by modified BTK model, spin polarizations of various materials, generally with low ferromagnetism, were …
-
Fluctuating and Phase -Stiff Proximity-Induced Superconductivity in Superconductor-Semiconductor Junctions
… than a factor of two) to be explained by simple Andreev reflection. Significant and abrupt changes in the semiconductor's 2D sheet resistance also suggest phenomenology beyond simple boundary effects.
-
Point contact spectroscopy studies of the iron based superconductors
… shown that apart from probing superconductors by Andreev reflection, PCS is also a useful technique to study exotic electron matter in correlated materials. The point contact junctions are made by two separate techniques: needle-anvil PCS and soft PCS. $dI/dV$ measured in the superconducting phase …
-
Generalization of the BTK Theory to the Case of Finite Quasiparticle Lifetimes
… the probability current densities for the Andreev reflection, the normal reflection, the transmission without branch crossing and the transmission with branch crossing are determined. Accordingly the electric current and the differential conductance curves are calculated numerically for Nb, …
-
Electronic and optical properties of thin-film superconductors and superconductor - semiconductor interfaces
… with A. Shnirlnan, a theoretical model for the Andreev reflection contributions to the current at the SN interfaces is developed using the tunneling Hamiltonian method. Both, the interference due to multiple Andreev reflection, and the electron-electron interaction in the normal metal, …
-
Towards the fabrication of suspended superconductor-graphene-superconductor Josephson junctions
… Josephson junctions which exhibit multiple Andreev reflection at temperatures of 4 K. and a Dirac peak near -0.4 V, all without any annealing of the graphene. We have also developed an annealing and lithography process which can clean graphene and preserve its cleaness during the rest of the …
-
Point contact studies of rare earth-transition metal compounds
… Co and Fe has been measured using point contact Andreev reflection (PCAR), and found to be in good agreement with previous results. In addition, bi-layers of Co/Y and Co/Cu have been used to demonstrate suppression of the spin polarisation of the Co underlayer via a nonmagnetic capping layer. The …
-
Josephson Interferometry Measurements in High-T(c) Grain Boundary Junctions
… the structure of the grain boundary interface. Andreev reflection at the (110) surface in d-wave superconductors leads to the formation of zero-energy quasiparticle surface states. It is predicted that these surface states lead to a suppression of the d-wave order parameter and formation of a …
-
Josephson Interferometry Measurements in High-Tc Grain Boundary Junctions
… the structure of the grain boundary interface. Andreev reflection at the (110) surface in d-wave superconductors leads to the formation of zero-energy quasiparticle surface states. It is predicted that these surface states lead to a suppression of the d-wave order parameter and formation of a …
-
Magnetotransport in superconductor to semiconductor junctions: multiple Andreev reflections and coupling to quantum hall states
… peaks in differential resistance due to multiple Andreev reflection. As the magnetic field is increased, the MAR peaks move toward lower voltages and disappear. The movement of the peaks is caused by the decrease of the superconducting gap with field.
-
Spin-triplet proximity effects in magnetically controlled heterostructures with s-wave superconductors
… temperature, *T*<sub>C</sub>, and point-contact Andreev reflection (PCAR) spectroscopy. The first two chapters of this thesis cover the basic physics underlying triplet pair generation and experimental methods. The following four chapters cover experimental results. Chapter 3 investigates S/F/F …
-
Engineering superconductivity in ballistic semiconductor nanowires
… is identified through conductance signatures of Andreev reflection. The second set of experiments, we focus on developing superconducting quantum wires through the development of selective-area epitaxy of Al to InSb nanowires. Epitaxial InSb–Al devices generically possess a BCS-like …
-
Investigations of nonlocal transport and current noise in mesoscopic normal metal-superconductor hybrid structures
… which higher-order processes such as correlated Andreev reflections at both interfaces are predicted to contribute. We verify the distance dependence of nonlocal transport in a superconducting wire to which several normal metal electrodes are attached and obtain a good agreement between the decay …
-
Manipulating superconductivity in cuprates with selective ultrafast excitation
… probes the superconducting order parameter via Andreev reflection and is sensitive to bosonic modes that couple to the quasiparticle spectrum. Recent work has shown that PCS can be used to detect a variety of correlated states that couple to electronic degrees of freedom. The technique has been …
-
Unconventional superconductivity in topological insulator and magnetic Josephson junctions
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms