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 20 for “"Berry curvature"”.
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Topological phenomena in ultracold atomic gases
… geometrical properties described by the Berry curvature. Bands with nonzero Berry curvature arise in key areas of current research, such as optical lattices with more than one band; strong artificial magnetic fields and 2D spin-orbit coupling. Topological solitons are also relevant to …
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Electronic Spin Coupled Nonadiabatic Dynamics
… spin and nuclear dynamics, namely the molecular Berry curvature effects. In the first part of the thesis, we demonstrate that the molecular Berry curvature effects can lead to spin-specific reaction rates and spin-dependent reaction pathway selection. In systems with odd number of electrons and …
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Implications of Vorticity and Disorder on Quantum Transport in Topological Semimetals
… and quantum kinetic frameworks, we analyze how Berry curvature and orbital magnetic moments generate charge and current responses in the presence of rotation and vorticity. The interplay between chirality, tilt, and Berry curvature leads to a family of vortical effects that mirror well-known …
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Quantum Geometry and Topology in Periodically-Strained Graphene
… out. The resulting bands carry significant Berry curvature and provide a favorable environment for the emergence of novel electron dynamics. In particular, the Berry curvature can induce an oscillating trajectory of an electron wavepacket transverse to an applied static electric field. …
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Nonreciprocal and Exotic Radiative Transfer in Type-I Magnetic Weyl Semimetals
… possess intrinsic nonreciprocity due to the Berry curvature, an internal, pseudo-magnetic field. In this dissertation, we explore thermal radiation from type-I magnetic Weyl semimetals in planar configurations in the far- and near-fields. First, we demonstrate that a planar interface between …
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Modelling of Berry phase and Fermi-level topologies for emergent quantum phenomena prediction in selected solid state systems
… construct tight-binding (TB) models to compute Berry curvature, surface state spectra, and Fermi arc patterns via WannierTools. To probe QPTs in SrSi2, we employ the Quantum Lattice environment to simulate a renormalized graphene lattice, mapping analogies between external perturbations and …
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Electromagnetic response of time-reversal breaking metallic phases in two dimensions
… magnetic fields, which corresponds to the Berry curvature on the Fermi surface. The alpha phase does not have that property. To go beyond the mean-field, we introduce the machinery of higher dimensional bosonization. Our preliminary results show that in the mean field limit of the bosonized …
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Aspects of symplectic dynamics and topology: gauge anomalies, chiral kinetic theory and transfer matrices
… quantum input to the symplectic form being the Berry curvature that encodes the spin-momentum locking. The (semi-)classical equations of motion are used in a kinetic theory setup to compute the gauge and singlet currents, whose conservation laws reproduce the nonabelian gauge and singlet …
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Hofstadter Physics and Composite Fermionic Phase in Moiré Systems
… and an effective magnetic field arising from Berry curvature, could be energetically favored under certain conditions. Our findings suggest that Moiré TMDs are promising candidates for realizing fractional Chern insulators and other exotic quantum phases, opening up new avenues for …
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Stoner magnetism and Berry phase in quantum materials
… solids often exhibit carrier bands with Berry phase in 𝑘 space, resulting in carriers behaving like spinning objects and generating orbital magnetization in position space. This thesis explores the impact of orbital magnetization arising in this way on the correlated electron phases. The …
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Quantum Transport in Topological Phases of Matter
… Magnus Hall effect, that allows one to probe Berry curvature in ballistic, time-reversal invariant systems that break inversion symmetry. Next, I present a detailed characterization of extrinsic Nernst effect in Dirac and Weyl semimetals, providing interpretation of existing experimental …
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The Electronic Compressibility of Rhombohedral Graphene Multilayers
… When these bands also have concentrated Berry curvature, the correlated phases may be topologically non-trivial. The low-energy bands of rhombohedral graphene multilayers possess both of these ingredients, making this a promising class of materials in which to search for correlated …
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Geometry and Topology of Quantum States in Quasicrystalline Systems
… alongside additional anomalous terms due to Berry curvature contributions. Fascinatingly, we also discover a so-called spiral holonomy in the effective band structure, in which circular trajectories result in evolution into an orthogonal state. We show that this feature is a result of the …
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Interplay between Correlation and Topology in Two-dimensional Systems
… is a nearly flat low-energy band with non-zero Berry curvature. This generalizes the familiar quantum Hall physics to a broader context, where both dispersion and quantum geometry can be varied. This thesis focuses on novel quantum phases in systems where three ingredients, kinetic energy, …
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Engineering light-matter interaction using two dimensional materials
… a specific circular polarization, leads to a net Berry curvature, giving rise to a finite transverse conductivity. Using this model, I predict the appearance of nonreciprocal chiral edge modes, their hybridization and waveguiding in a nanoribbon geometry, and giant polarization rotation in …
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Strongly Correlated 2D Electronic Systems: Interplay between Band Topology and Electron-electron Interaction
… field acting on LLL and momentum space periodic Berry curvature in a topological Chern band. We considered spinful electrons at total filling 𝜈 = 1 and studied the spin wave dispersion in the presence of Coulomb potential. We found that compared to uniform magnetic field, the spin stiffness …
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Spectroscopy of Topological Materials and their Technological Applications
… unique Landau level quantization and large Berry curvature-induced anomalous Nernst effect. We describe measurements of nonlinear Hall effects in these materials which highlight their possible use in energy harvesting and terahertz applications. We also describe ideas of using topological …
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Investigation on High-Mobility Graphene Hexagon Boron Nitride Heterostructure Nano-Devices Using Low Temperature Scanning Probe Microscopy
… It has been associated with the non-zero valley Berry curvature due to the gap opening and the nonlocal signal has been interpreted as the signature of the topological valley Hall effects. However, the nature of such signal is still disputed in the community, due to the vanishing density of …
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Electric and thermoelectric properties of antiferromagnetic metals
… Non-collinear AF Mn$_3$Sn has a non-zero Berry curvature from time reversal symmetry breaking, and therefore have a large anomalous Hall effect (AHE) and large ANE at room temperature. A large zero-field ANE is observed in the inverse-triangular spin state and collapses upon entering the …
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Exploring linear and nonlinear electromagnetic responses in topological materials
… which reveals opposing contributions between the Berry curvature and the density of states. We then apply our results to study the Kerr effect in the moiré Chern insulator, which exemplifies the experimental pertinence of spatially inhomogeneous fields in such systems, given their large effective …