Showing papers by "C. A. Balseiro published in 1990"
TL;DR: It is shown that charge accumulation in the quantum well is large enough to produce a bistability in the negative-differential-resistance region of the current-voltage curve.
Abstract: We calculate in the effective-mass approximation the current-voltage characteristic for an ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As-GaAs-${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As heterostructure. Our calculation includes the effect of electron-electron interaction in a self-consistent way. We show that charge accumulation in the quantum well is large enough to produce a bistability in the negative-differential-resistance region of the current-voltage curve.
26 citations
TL;DR: Etude des proprietes de l'etat fondamental du modele d'Heisenberg antiferromagnetique de spin 1/2 anisotrope unidimensionnel avec une interaction d'Ising de seconds voisins, antiferrosyntique en competition.
Abstract: We study the ground-state properties of the one-dimensional anisotropic spin-1/2 antiferromagnetic Heisenberg model with competing antiferromagnetic second-neighbor Ising interaction. Using the modified Lanczos method, we obtain the phase diagram in parameter space and different correlation functions, which we use to characterize the different phases. For small next-nearest-neighbor parameters we evaluate the critical exponent \ensuremath{\eta} of the spin-spin correlation function. We find good agreement between the numerical results and those obtained using the Luther and Peschel approach.
17 citations
TL;DR: It is shown that the problem of single-particle excitation can be mapped onto that of a hole in a polarized antiferromagnetic Heisenberg model and the distortion of the superfluid order parameter in the vicinity of the quasiparticle and the connection with the pairing-bag problem is discussed.
Abstract: We study the one-particle excitations in strong-coupling superconductors described by a negative-U Hubbard Hamiltonian. We show that the problem of single-particle excitation can be mapped onto that of a hole in a polarized antiferromagnetic Heisenberg model. We discuss\char22{}using a self-consistent diagrammatic approach\char22{}the distortion of the superfluid order parameter in the vicinity of the quasiparticle and the connection with the pairing-bag problem.
7 citations
TL;DR: In this paper, exact results for small clusters of CuO2 units including intra-atomic and interatomic Coulomb interactions are presented for doped and undoped systems and the results are in qualitative agreement with spectroscopic experiments.
Abstract: We present exact results for small clusters of CuO2 units including intra-atomic and interatomic Coulomb interactions. We calculate one-particle spectral densities for doped and undoped systems and show that the results are in qualitative agreement with spectroscopic experiments. We also present results for spin and charge dynamics as well as the current-current correlation functions.
5 citations