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 20 of 41 for “"Tight-Binding Model"”.
-
A tight-binding analysis of the electronic properties of III-nitride semiconductors
… parts, both of which are underpinned by the tight-binding model. The first part covers our implementation of the tight-binding model in conjunction with the Berry phase theory of electronic polarisation to probe the atomistic origins of spontaneous polarisation and piezoelectricity as well as …
-
Many-Body Effects on the X-Ray Spectra of Metals
… using a one-dimensional nearest-neighbor tight-binding model of a metal.
-
Theoretical study of hydrogen in [alpha]-YH[subscript x] and on Si(111) surface
… technique. With this in mind, an empirical tight binding model is constructed for the simpler Si:H system and applied in a molecular dynamics simulation to study the hydrogen vibration on Si(111) surface. Our empirical tight binding model is able to provide an efficient and yet accurate …
-
Simulation of graphene electronic devices
… third nearest-neighbour interactions within a tight binding model. A comparison of the current-voltage characteristics of MOS structures formed on graphene nanoribbons and carbon nanotubes suggests that the nanoribbon devices may be better for switching applications. Conductivities of graphene …
-
Electronic band structure of III-V quantum dots using tight-binding and the k.p approximation
… approximation and O(N) moments based tight-binding model for electronic band structure calculations are implemented for several cases relating to quantum dot nanostructures where various mechanical models are investigated. First, a comparison is made between the two for an equivalent …
-
Atom-by-Atom Substitution of Transition Metals in Gallium Arsenide and Visualization of Hole-Mediated Interactions
… findings, which can be explained using tight-binding model calculations, reveal a strong dependence of ferromagnetic interaction on crystallographic orientation. This anisotropic interaction can potentially be exploited by growing oriented Ga1-xMnxAs structures to enhance the …
-
Floquet theory of electronic stopping processes of projectiles in solids
… Moreover, it goes beyond nonlinear models for the homogeneous electron gas, which assume ideal metal hosts. The theory exploits a discrete symmetry in the trajectory of the projectile following a direction of crystalline periodicity, which allows a treatment based on Floquet theory …
-
Locality of forces in molecular systems
… a basic requirement for most modern methods for modelling systems of thousands of atoms or more. Despite its widespread use, the assumption of locality remains largely unfounded in the underlying quantum mechanical description. This work presents an algorithm for quantifying the locality of …
-
Topological Phases in Perovskite Iridates with Strong Spin-Orbit Coupling
… of such bulk nodal-line band degeneracy in the tight-binding model. Thirdly, we propose that a topological insulator can exist in a two-dimensional single layer Iridium oxide superlattice under certain lattice distortions; a tight-binding model is constructed using the basis of an effective J …
-
Topics in the theory of semiconductors: I. Novel semiconductors II. Uniaxial stress dependence of deep impurities
… are predicted with a nearest-neighbor, tight-binding model. Gel_xS~ is a semiconductor-metal alloy which may have applications in infrared detection or as a Gunn device. Doping anomalies are found: deep impurity levels in the band gap of Ge necessarily make deep-to-shallow transitions as …
-
DNA Electronics
… a unique place in this area. We predict, using a tight-binding model, that spin-dependent transport can be observed in short DNA molecules sandwiched between ferromagnetic contacts. In particular, we show that a DNA spin-valve can be realized with magnetoresistance values of as much as 26% for Ni …
-
Anderson Localization in Two-Channel Wires with Correlated Disorder: DNA as an Application
… disorder was studied using a single-electron tight-binding model. Calculations were within second-order Born-approximation to second-order in disorder parameters. An analytical expression for localization length as a functional of correlations in potentials was found. Anderson localization in …
-
Self-Consistent Study of Topological Superconductivity in Two-Dimensional Quasicrystals
… peaks, they have no periodicity. We generalize a tight-binding model for TSC in two dimensions, which was originally proposed for square lattice systems, for QCs. As the most fundamental examples, the Penrose and Ammann-Beenker QCs are studied. QCs are inherently fractal, and characterized by …
-
Giant Magnetoresistance in Multilayers
… through a realistic third-nearestneighbor tight-binding model with s, p and d orbitals. The Landauer-Biittiker formula was used to calculate the conductance of the two spin channels. The method is based on efficiently calculating the Green's function of the leads and the slab using the …
-
Quantum Simulation of Many-body Systems with Superconducting Qubits
… to study the dynamics of a particle under the tight-binding model, and probe quantum information propagation by measuring out-of-time-ordered correlators (OTOCs). Using a 4×4 qubit array, we probe entanglement across the energy spectrum of a hard-core Bose-Hubbard lattice by extracting …
-
Electronic properties of bilayer graphene in a steady magnetic field
… in a steady, parallel magnetic field. Using the tight–binding model, and taking into account relevant tight–binding parameters, we find a new contribution to the electronic Hamiltonian describing the orbital effect of the magnetic field. We consider the effect of the magnetic field on the …
-
Search for evidence of fermi surface nesting in Bi₂Sr₂Ca₁Cu₂O₈
… A calculation of Im(-1/ε) was performed using a tight binding model and it was found that the features associated with the Fermi surface (from this TB calculation) were too small to be seen in our spectra. We interpret this problem to be associated with the presence of thermal diffuse scattering.
-
Fluctuations and exciton dynamics in molecular semiconductors
… crystals can be described with a common tight-binding model and analyze how both the crystal structure and the π-topology impact the electronic structure. With this consistent description of the electronic states, it is discussed how fluctuations act on different materials and how they …
-
Interplay between chemical bonding, band structure and charge transport in thermoelectric chalcogenides
… charge transport are also studied. Afterwards, a tight-binding model is defined for the band structure of crystalline group IV chalcogenides with metavalent bonding and octahedral coordination, which relates band gap and effective mass tensor to intuitive chemical coordinates. The model can …
-
Synthetic Topological Quantum Matter in Nanostructured 2D Materials for Quantum Information Processing
… approximations commonly used to solve it. The tight-binding model is derived, and its application to moiré materials is demonstrated, followed by a comparison with the continuum approach. We then discuss mean-field methods, specifically Density Functional Theory (DFT) and Hartree-Fock. In the …
Page 1 of 3