Topological defects and the spin glass phase of cuprates

Abstract

We propose that the spin glass phase of cuprates is due to the proliferation of topological defects of a spiral distortion of the antiferromagnet order. Our theory explains straightforwardly the simultaneous existence of short range incommensurate magnetic correlations and complete a-b symmetry breaking in this phase. We show via a renormalization group calculation that the collinear O(3)/O(2) symmetry is unstable towards the formation of local non-collinear correlations. A critical disorder strength is identified beyond which topological defects proliferate already at zero temperature.c EDP Sciences

Impurity effect on the diagonal incommensurate spin correlations inLa2−xSrxCuO4

“…17,18 In this model the incommensurate magnetic peaks are purely magnetic in origin and have nothing to do with charge ordering, in contrast to the stripe model. They also suggested neutron-scattering experiments to determine if the incommensurate magnetic peaks originate from the stripe or the spiral phase.…”

“…The Zn concentration dependence of ⑀ indicates that ␥ ϳ 3, which is roughly consistent with the prediction. 17,18 However, the stripe model also can explain this behavior if one assumes that the holes around the Zn sites are slightly localized ͑ϳ0.15 hole/Zn͒ so that the effective hole density is reduced. This is consistent with the quantitative transport properties that the resistivity increases and the Hall coefficient decreases with Zn doping in La 1.85 Sr 0.15 CuO 4 .…”

Topological stripelike coreless textures with inner incommensurability in two-dimensional Heisenberg antiferromagnet

“…We emphasize here a topological difference between these Z 2 defects and those that have been used in the dipole model. 21 The latter describe a change of spiral chirality, clockwise or counter-clockwise twist.…”

Dissipative dynamics of topological defects in frustrated Heisenberg spin systems

“…In addition, the energy of the vortex-antivortex pair should be bounded below at distances of the order of few lattice spacings, which is the intrinsic cutoff of the theory. Because the procedure that we describe in the following does not depend on the exact form of the static solution, we will refer to a static topological defect solution Ψ v specifying only at the end of the calculations the differences between the cases (10) and (11).…”

“…This situation may be realized in lightly doped cuprate superconductors. 4,5,6,7,8,9,10,11,12 The main characteristic of the noncollinear state is that the spin configuration must be described by a set of three orthonormal vectors or, alternatively, by a rotational matrix which defines the orientation of this set with respect to some fixed reference frame. As a consequence, the order-parameter space is isomorphic to the three-dimensional rotational group SO (3), and in the low-temperature phase, when the rotational symmetry is fully broken, three spin-wave modes are present in the system, instead of two, as in the nonfrustrated case.…”