Showing papers by "C. A. Balseiro published in 2002"
TL;DR: A theoretical description of electron spin resonance (ESR) in 1D interacting metals is given, with primary emphasis on carbon nanotubes, and the resulting ESR spectrum is analyzed using a low-energy field theory.
Abstract: A theoretical description of electron spin resonance (ESR) in 1D interacting metals is given, with primary emphasis on carbon nanotubes. The spin-orbit coupling is derived, and the resulting ESR spectrum is analyzed using a low-energy field theory. Drastic differences in the ESR spectra of single-wall and multiwall nanotubes are found. For single-wall tubes, the predicted double peak spectrum is linked to spin-charge separation. For multiwall tubes, a single narrow asymmetric peak is expected.
69 citations
TL;DR: Exact calculations show the occurrence of spectroscopic and magnetic mirages at the antipodes of the impurity location, and predict the existence of a strong magnetic mirage in the experimentally realizable elliptic corral.
Abstract: We present exact results for magnetic impurities in nanoscopic systems with focusing properties. We analyze the spectroscopic and magnetic properties of Kondo, intermediate valence, and magnetic impurities on a sphere with a metallic surface. Exact calculations show the occurrence of spectroscopic and magnetic mirages at the antipodes of the impurity location. Comparison with calculations performed using effective models validates previous calculations of spectroscopic mirages. Our results predict the existence of a strong magnetic mirage in the experimentally realizable elliptic corral.
22 citations
TL;DR: In this article, the frequency and temperature dependence of the impurity spectral density ρ i (ω,T) for impurities in small systems that are either isolated or in contact with a reservoir is analyzed.
Abstract: We present results for the spectral properties of Kondo impurities in nanoscopic systems. Using Wilson's renormalization group we analyze the frequency and temperature dependence of the impurity spectral density ρ i (ω,T) for impurities in small systems that are either isolated or in contact with a reservoir. We have performed a detailed analysis of the structure of ρ i (ω,T) for ω around the Fermi energy for different Fermi energies relative to the intrinsic structure of the local density of states. We show how the electron confinement energy scales introduce features in the frequency and temperature dependence of the impurity spectral properties.
17 citations
TL;DR: In this paper, the behavior of a vortex system in the presence of two types of pinning forces is modeled, one caused by a dense point disorder and the other caused by the artificial Bitter pinning introduced by means of a magnetic decoration.
Abstract: We model the behavior of a vortex system in the presence of two types of pinning forces. One is caused by a dense point disorder. The other is the artificial Bitter pinning introduced by means of a magnetic decoration. Westudy static and dynamical properties of the system as a function of the vortex density. the temperature, and the relative intensity of the pinning forces. We find different dynamical behaviors near the solid-liquid transition. Our numerically obtained double decoration patterns are very similar to the ones observed experimentally.
6 citations
TL;DR: In this article, the behavior of a vortex array in a periodic pinning potential with the geometry of triangular and kagome lattices was analyzed by looking at the individual squared displacement of the vortices and a suitable order parameter.
Abstract: We study the behavior of a vortex array in a periodic pinning potential with the geometry of triangular and kagome lattices. We analyze the system by looking at the behavior of the individual squared displacement of the vortices and a suitable order parameter, called the pinned fraction, as a function of temperature. For the first, second and third matching fields we show the phase diagrams indicating several stages of vortex lattice pinning and melting. At low temperatures the kagome pinning potential shows a phase with rotating vortex triangles and geometric frustration.
4 citations
TL;DR: In this article, the authors present results for Kondo impurities in nanoscopic systems using Wilson's numerical renormalization group and analyze two different situations: an isolated system with a discrete spectrum of well-defined energy levels and a fixed number of electrons and a nanoscopic system weakly coupled to a macroscopic reservoir.
Abstract: We present results for Kondo impurities in nanoscopic systems. Using Wilson's numerical renormalization group we analyze two different situations: an isolated system with a discrete spectrum of well-defined energy levels and a fixed number of electrons and a nanoscopic system weakly coupled to a macroscopic reservoir. In the latter case, new regimes not observed in macroscopic homogeneous systems are induced by the confinement of conduction electrons. These new confinement-induced regimes are very different depending on whether the Fermi energy is at resonance or between two quasi-bound states.
3 citations
TL;DR: In this article, the authors simulate a magnetic double decoration experiment, modeling the problem as a 2D vortex system in the presence of two types of pinning forces: Bitter pinning introduced by a previous magnetic decoration and dense point disorder.
Abstract: We simulate a magnetic double decoration experiment, modeling the problem as a 2D vortex system in the presence of two types of pinning forces. One represents the Bitter pinning introduced by a previous magnetic decoration, and the other is the dense point disorder. We study the freezing of the vortex lattice and analyze the topological order of our double decoration patterns.
TL;DR: In this article, the behavior of magnetic impurities in nanoscopic systems with focusing properties was studied and exact calculations were performed to obtain spectroscopic and magnetic mirages at the antipodes of the impurity location.
Abstract: We study the behavior of magnetic impurities in nanoscopic systems with focusing properties. In this paper, we analyze the spectroscopic and magnetic properties of Kondo, intermediate valence and magnetic impurities on a sphere with a metallic surface. Using exact calculations, we obtain important spectroscopic and magnetic mirages at the antipodes of the impurity location. When compared with calculations performed using effective models our results validate previous calculations of spectroscopic mirages. These calculations can be extended to other systems with focusing properties like quantum corrals where a similar behavior is expected.