Localized Hole States in a Two‐Dimensional Antiferromagnet

Abstract

A connection between band excitations and sublattices in the Hubbard antiferromagnet leads to the appearance of two types of localized states arising due to an impurity on the "own" (for given band excitations) and "alien" sublattices. In the case of the substitutional impurity the conditions of the appearance of these localized states, their energies and symmetries are obtained in dependence on the ratio of the exchange constant to the hopping matrix element. These dependences and the number of the localized levels are different for the two types of states mentioned.

Interaction of a magnetic impurity with strongly correlated conduction electrons

“…Several authors studied the influence of non-magnetic impurities in systems with strongly correlated electron in order to explain the magnetic properties of the undoped or weakly doped host materials of the high-temperature superconductors (e.g., La 2 CuO 4 ). The considered impurities stem from substituting Sr for La, [8][9][10] or from substitutions in the CuO 2 planes, i.e., Zn for Cu [11][12][13] and S for O. 14 Nagaosa et al 15 treated magnetic impurities in an undoped two-dimensional Heisenberg antiferromagnet by adding external spins with a different exchange coupling constant.…”

“…superconductors (e.g., La 2 CuO 4 ). The considered impurities stem from substituting Sr for La, [8][9][10] or from substitutions in the CuO 2 planes, i.e., Zn for Cu [11][12][13] In this paper, we study the coupling of a single magnetic impurity to strongly correlated electrons moving on a lattice. The latter are described by a Hubbard Hamiltonian and the total Hamiltonian must, therefore, go beyond that of the single-site Anderson impurity model.…”

Bound-hole states induced by excess oxygen inLa2CuO4+δRubin1, Sherman2 1996Phys. Rev. BSelf Cite3000View full textAdd to dashboardCite

“…This ordering has a pronounced effect on bound states that can be most easily seen by the example of a substitutional isoelectronic impurity in the copper position of the CuO 2 plane. 7 For a given Néel state carriers, which are characterized by a certain value of the z projection of the spin S z , are mainly located on one magnetic sublattice. We shall call it the ''A'' sublattice for these carriers, in contrast to the ''B'' sublattice with a smaller wave-function amplitude.…”

“…As a consequence, two systems of bound states related to perturbations on the ''A'' and on the ''B'' sublattices arise. 7 For the other Néel state analogous bound states, differences only in the sign of S z appear. A substitutional isoelectronic impurity in the oxygen position of the CuO 2 plane produces equal perturbations on both sublattices.…”