Showing papers by "C. A. Balseiro published in 1995"
TL;DR: The static on-site susceptibility decreases as the interactions in the chain are turned on and this is interpreted as an increase of the Kondo temperature.
Abstract: Using numerical techniques we study the zero temperature properties of a substitutional magnetic impurity in a one-dimensional correlated system described by the Hubbard model with repulsive interaction $U$. We find that, while the static spin correlation maintains a $2k_F$ periodicity, the charge correlations show Friedel oscillations with a $4k_F$ periodicity for large values of $U$. The static on-site susceptibility decreases as the interactions in the chain are turned on and we interpret this as an increase of the Kondo temperature. For large values of $U$ the short range antiferromagnetic correlations dominate over the collective Kondo singlet formation.
9 citations
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TL;DR: In this article, the authors studied the persistent currents in a one-dimensional ring with a junction, described by the negative-U Hubbard model using exact diagonalization methods, and showed that for sufficiently large values of J t′ the persistent current changes sign, giving rise to what is known as a π-junction.
1 citations
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TL;DR: In this paper, the question of whether an anisotropic gap is compatible with localized states in the normal phase was addressed, where a superconductor to insulator transition is observed in the underdoped regime.
Abstract: We address the question of whether an anisotropic gap $d_{x^2-y^2}$ symmetry is compatible with localized states in the normal phase. The issue is important in high $T_c$ superconductors where a superconductor to insulator transition is observed in the underdoped regime, together with a number of experiments that support $d$-wave pairing. We find a reentrant behavior of superconductivity in the strongly disorder phase.