Topological defects and the spin glass phase of cuprates

¹ Max-Planck-Institut für Physik komplexer Systeme Nöthnitzer Str. 38, D-01187 Dresden, Germany
² Department of Physics, Boston University - Boston MA 02215, USA
³ Institut de Physique Théorique - Pérolles, CH-1700 Fribourg, Switzerland

Received: 6 July 2001
Accepted: 8 October 2001

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.