Landau levels in the presence of topological defects (original) (raw)
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Landau Levels In the Presence of Disclinations
Physics Letters A, 1994
This work is an investigation of the influence ofa disclination on the spectrum of an electron or hole in a magnetic field in the framework of the theory of defects/three-dimensional gravity of Katanaev and Volovich. The presence of the defect reduces the degeneracy of the Landau levels to a finite value, except for very particular deficit angles. Inclusion of the self-interaction in the study further breaks the degeneracy. Exact wavefunctions and energy eigenvalues are found for special values of the magnetic field.
Landau quantization for a neutral particle in the presence of topological defects
Physical Review D, 2009
In this paper we study the Landau levels in the non-relativistic dynamics of a neutral particle which possesses a permanent magnetic dipole moment interacting with an external electric field in the curved spacetime background with the presence or absence of a torsion field. The eigenfunction and eigenvalues of Hamiltonian are obtained. We show that the presence of the topological defect breaks the infinite degeneracy of the Landau levels arising in this system. We also apply a duality transformation to discuss this same quantization for a dynamics of a neutral particle with a permanent electric dipole moment.
Landau quantization for an induced electric dipole in the presence of topological defects
2010
In this contribution we investigate the non-relativistic quantum dynamics of induced electric dipoles in the presence of a topological defect. We propose an analog of Landau quantization for neutral atoms, where a electric dipole is induced by the electromagnetic field configuration. We investigate this system in the presence of a topological defect and show that it breaks the infinite degeneracy of Landau levels.
Single-Particle Quantum States in a Crystal with Topological Defects
Physical Review Letters, 1998
The influence of frozen-in topological defects in a crystal on the long-wavelength quantum states of a particle is considered. In the continuum limit of a conveniently defined tight-binding model one is led to a covariant Schrödinger equation on a Riemann-Cartan manifold. When the tight-binding transfer energies are assumed to depend on the local lattice deformations caused by the defects, additional noncovariant terms are generated in the Hamiltonian. These terms generate bound states of the particle to edge dislocations and enhance the scattering of particles on screw dislocations. [S0031-9007(98)05432-5]
Physics Letters A, 2016
In this paper, we investigate the influence of a screw dislocation on the energy levels and the wavefunctions of an electron confined in a two-dimensional pseudoharmonic quantum dot under the influence of an external magnetic field inside a dot and Aharonov-Bohm field inside a pseudodot. The exact solutions for energy eigenvalues and wavefunctions are computed as functions of applied uniform magnetic field strength, Aharonov-Bohm flux, magnetic quantum number and the parameter characterizing the screw dislocation, the Burgers vector. We investigate the modifications due to the screw dislocation on the light interband absorption coefficient and absorption threshold frequency. Two scenarios are possible, depending on if singular effects either manifest or not. We found that as the Burgers vector increases, the curves of frequency are pushed up towards of the growth of it. One interesting aspect which we have observed is that the Aharonov-Bohm flux can be tuned in order to cancel the screw effect of the model.
Spin wave interaction with topological defects
Journal of Physics: Condensed Matter, 2009
Following our earlier gauge field theory analysis of the diffusion and interactions of classical and quantum waves with topological defects in solids (screw and edge dislocations), we present the analysis of the interaction of a classical spin wave with a screw dislocation studied within the Heisenberg ferromagnet model in which spins are located on a lattice containing dislocations. We show that the spin wave interaction with the screw dislocation shows a similarity to the Aharonov-Bohm-like deflection found previously for scattering of acoustic waves on the same type of defects.
On the binding of electrons and holes to disclinations
Physics Letters A, 1994
In this work we study the bound states of electrons and holes to disclinations in the framework of the theory of defects/threedimensional gravity of Katanaev and Volovich. We find that positive disclinations repel both electrons and holes while negative disclinations act as attractors to both, giving rise to bound states. We compute the wavefunctions and the eigenvalues for these bound states.
Anomalous Defects and Their Quantized Transverse Conductivities
International Journal of Modern Physics A, 1998
Using a description of defects in solids in terms of three-dimensional gravity, we study the propagation of electrons in the background of disclinations and screw dislocations. We study the situations where there are bound states that are effectively localized on the defect and hence can be described in terms of an effective (1+1)-dimensional field theory for the low energy excitations. In the case of screw dislocations, we find that these excitations are chiral and can be described by an effective field theory of chiral fermions. Fermions of both chirality occur even for a given direction of the magnetic field. The "net" chirality of the system however is not always the same for a given direction of the magnetic field, but changes from one sign of the chirality through zero to the other sign as the Fermi momentum or the magnitude of the magnetic flux is varied. On coupling to an external electromagnetic field, the latter becomes anomalous and predicts novels conduction pr...
In this work, we use the geometric theory of defects to investigate a continuous distribution of screw dislocations. We analyze the dynamics of a quantum particle in the presence of a density of screw dislocations. We obtain the energy levels and eigenfunctions for the particle in this background. We demonstrate that this quantum dynamics is similar to the dynamics of a charged particle in the presence of an external magnetic field. In addition, we introduce an external magnetic field and perform the calculations of the eigenfunctions and eigenvalues for the particle in this case.
Aharonov–Bohm effect in the presence of a density of defects
Physics Letters A, 2002
In this work we study the quantum dynamics of a particle in the presence of a density of defects in continuous media. We solve the Schrödinger equation for a quantum particle in the presence of a distribution of wedge disclination and obtain the eigenfunctions and eigenvalues for this case. We analyze the Aharonov-Bohm effect for bound state.