JETP Letters

, Volume 96, Issue 6, pp 385–390

Pseudogap phase in cuprates: Oxygen orbital moments instead of circulating currents

Authors

    • Department of Theoretical PhysicsUral Federal University
Article

DOI: 10.1134/S0021364012180087

Cite this article as:
Moskvin, A.S. Jetp Lett. (2012) 96: 385. doi:10.1134/S0021364012180087

Abstract

Circulating current loops within the cuprate unit cell are proposed to play a key role in the physics of the pseudogap phase. However, main experimental observations motivated by this sophisticated proposal and seemingly supporting the circulating current model can be explained within a simple and physically clear microscopic model. It has been argued that, instead of a well-isolated Zhang-Rice (ZR) singlet 1A1g, the ground state of the hole center [CuO4]5− (cluster analog of Cu3+ ion) in cuprates should be described by a complex 1A1g-1,3B2g-1,3Eu multiplet, formed by a competition of conventional hybrid Cu 3d-O 2p\(b_{1g} (\sigma ) \propto d_{x^2 - y^2 }\) state and purely oxygen nonbonding O 2 states with a2g(π) and eux, y(π) symmetry. In contrast to inactive ZR singlet we arrive at several novel competing orbital and spin-orbital order parameters, e.g., Ising-like net orbital magnetic moment, orbital toroidal moment, intra-plaquette’s staggered order of Ising-like oxygen orbital magnetic moments. As a most impressive validation of the non-ZR model we explain fascinating results of recent neutron scattering measurements that revealed novel type of magnetic ordering in pseudogap phase of several hole-doped cuprates.

Copyright information

© Pleiades Publishing, Ltd. 2012