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.
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Showing 1 to 20 of 40 for “"rashba"”.
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Equilibration of deep neural networks and carrier chirality in Rashba systems
… the decay of non-equilibrium states in strongly Rashba-coupled systems at low temperature. Deep learning is a conceptually simple, highly effective, and widely used tool, yet there remains insufficient understanding for why it works. The optimisation of deep neural networks with common algorithms …
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Interdimensional effects in systems of fermions
… and heterostructure materials with large Rashba spin-orbit coupling along an interface. In all of these materials, the electron's spin is responsible for exotic behaviour along either a surface or an interface. Interdimensional models have previously been used to analyze systems which …
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High Pressure Quantum Oscillation Study of BiTeI and Bi2Te3
… in this thesis investigates the behaviour of the Rashba semi-conductor BiTeI and of the topological insulator $\text{Bi}_2\text{Te}_3\,$ under pressure. Using Shubnikov-de Haas quantum oscillation measurements, the evolution of the Fermi surface of both materials was tracked as a function of …
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MAJORANA FERMION IN TOPOLOGICAL SUPERCONDUCTOR AND MOTT‐SUPERFLUID TRANSITION IN CIRCUIT‐QED SYSTEM
… states in the spin-singlet superconductor with Rashba and Dresselhaus (110) spin-orbit couplings. In Chapter 3, we use Keldysh non-equilibrium Green function method to study the two-lead tunneling in the superconducting nanowire with Rashba and Dresselhaus spin-orbit couplings with/without …
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Phase coherent transport phenomena in HgTe quantum well structures
… It exhibits large Zeeman spin splitting and Rashba spin-orbit splitting. The latter is at least four to five times larger than in III-V semiconductors. Initially a short review on the transport theory was presented. The main focus as on quantisation effects that are important to understand …
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SPIN-ORBIT COUPLING IN STRONGLY CORRELATED SYSTEMS
… it is shown that a possible nonlinear Rashba effect can emerge in such a system. It can explain the presence of giant Rashba constants in some two-dimensional devices.
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Spin Properties of Heavy Holes in Low-Dimensional Quantum Electronic Devices
… gap, and the interplay between Dresselhaus and Rashba SOI could be achieved in a device with completely tunable symmetry of the quantum confinement. While fabrication methods exist that allow for tunable Rashba SOI, they are expensive and difficult to reproduce. Here we present a new method of …
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Spin-orbit or Aharonov-Casher edge states in semiconductor systems
… by the Aharonov-Casher vector potential or Rashba-type spin-orbit interaction using quantum transport in InGaAs/InAlAs herterostructures. The Aharonov-Casher effect is electromagnetically dual to the Aharonov-Bohm effect and is predicted to lead to edge states in a parabolic confinement at …
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Charge Carrier Relaxation in Halide Perovskite Semiconductors for Optoelectronic Applications
… still debated and an indirect bandgap due to a Rashba splitting has been suggested. In this thesis, we study the early-time carrier relaxation and its impact on photoluminescence emission. We first study ultrafast carrier thermalization processes using 2D electronic spectroscopy and extract …
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Bandstructure calculations for holes in GaAs and simulations of dc conductance in electron quantum point contacts
… k•p theory. Our calculations explicitly include Rashba and Dresselhaus spin-orbit terms. The effective mass of the holes at the zone center is calculated. The calculations show that the Rashba and Dresselhaus terms change the hole bandstructure and should not be ignored. We looked at the accuracy …
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Spin-mixing and transport through superconducting interlayers in ferromagnetic Josephson junctions
… barriers,incorporating spin-mixer interfaces and Rashba spin-orbit coupling. The research focuses on equilibrium spin-transport through intermediary superconducting regions for which experimental and theoretical studies are limited. The behaviour of singlet and triplet pair components in …
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EMERGENT PHENOMENA AND NOVEL DEVICES BASED ON SPIN-ORBIT COUPLING AT COMPLEX OXIDE INTERFACES
… building block of such applications is a strong Rashba SOC coupled to a spin-injecting magnetic layer and utilizes a spin-to-charge conversion as the transduction mechanism. This thesis explores the emergent phenomena and quantum phases at heterostructures and interfaces with a broken symmetry …
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Electrical control of spin dynamics in spin-orbit coupled ferromagnets
… originating from the spin-Hall effect and a Rashba spin-orbit field have both been reported in these materials. These spin-orbit torques may allow commercialisation of magnetic random access memories with higher efficiency than previous technologies. However, the exact origin of the torques …
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Topics in multi-component ultracold gases and gauge fields
… we discuss various properties of bosons with Rashba-Dresselhaus spin-orbit coupling, which is a special type of non-Abelian gauge field. We investigate the stability of Bose-Einstein condensates with Rashba-Dresselhaus spin-orbit coupling, and show that the condensates are stable against …
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Theory of d₀ perovskites and their heterostructures
… layer is then investigated further to understand Rashba interactions and their connection with microscopic material parameters. Next the optical conductivity of quantum confined t₂[subscript g] bands is investigated. Finally some possible future work based on the ideas developed in this thesis are …
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Quantum transport properties of charge, spin and orbital angular momentum in two-dimensional materials
… sub-rede e o acoplamento spin-órbita de Bychkov-Rashba afetam seus estados de spin-Hall quântico. Mostramos explicitamente que essa classe de sistemas pode ser conduzida para uma fase isolante topológica de Anderson na presença de desordem suficientemente forte. Realizamos cálculos da …
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Effects of asymmetry on electron spin dynamics in gallium arsenide quantum wells
… to provide the first direct measurement of the Rashba coefficient. There is good agreement with k.p theory at low temperatures; however there is an unexplained increase with temperature.<br/>Spin dynamics measurements were carried out on quantum wells with asymmetric alloy composition. Through …
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Aspects of Dzyaloshinskii-Moriya Interaction in Two Dimensional Magnetic Structures
… DMI. In the next step, I show addition of Rashba spin-orbit coupling (RSOC) with the spin-polarized conduction electron band produces the DMI between two magnetic ions. The essential feature of this DMI is: the coupling strength increases with the strength of RSOC, but decreases signi …
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Magnetic domain walls driven by interfacial phenomena
… in ultrathin ferromagnets. We also show that the Rashba field, often reported in materials with strong spin-orbit coupling, does not contribute to the observed efficient domain-wall motion. The anomalous dynamics instead emerges from the spin Hall effect: a charge current in the nonmagnetic heavy …
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Time-Resolved Studies of Magnetic and Non-Magnetic Narrow-Gap Semiconductors
… interaction in NGS on the dynamics, how large Rashba spin splitting in these materials affect the spin coherence life time, and carrier/spin dynamics in ferromagnetic semiconductor structures.
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