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

Abstract

Circulating current (CC) 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 CC model can be explained in frames of a simple and physically clear microscopic model. We argue that instead of a well-isolated Zhang-Rice (ZR) singlet ${}^1{A}_{1g}$ the ground state of the hole center [CuO${}_4$]${}^{5-}$ (cluster analog of Cu${}^{3+}$ ion) in cuprates should be described by a complex ${}^1{A}_{1g}$-${}^{1,3}{B}_{2g}$-${}^{1,3}{E}_u$ multiplet, formed by a competition of conventional hybrid Cu 3d-O 2p $b_{1g}(\sigma )\propto d_{x^2-y^2}$ state and {\it purely oxygen nonbonding} O 2p$\pi$ states with $a_{2g}(\pi )$ and $e_{ux,y}(\pi )$ symmetry. In contrast with 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.

6 pages, 3 figures, accepted for publication in JETP Lett

References in corpus (7)

• Polar Kerr Effect Measurements of YBa2Cu3O6+x: Evidence for Broken Symmetry Near the Pseudogap Temperature
• From a single-band metal to a high-temperature superconductor via two thermal phase transitions (Supporting Material)
• From a single-band metal to a high-temperature superconductor via two thermal phase transitions
• Orbital currents in extended Hubbard models of high-T${}_c$ cuprates
• Absence of time reversal symmetry breaking in La_{2-x}Sr_{x}CuO_{4}
• Evidence for Intra-Unit-Cell magnetic order in Bi2Sr2CaCu2O8+d
• Numerical analysis of three-band models for CuO planes as candidates for a spontaneous T violating orbital current phase

Cited by in corpus (13)

• A global inversion-symmetry-broken phase inside the pseudogap region of YBa${}_2$Cu${}_3$O${}_y$
• Intra-Unit-Cell magnetic correlations near optimal doping in $\mathrm{YB}{\mathrm{a}}_2\mathrm{C}{\mathrm{u}}_3{\mathrm{O}}_{6.85}$
• Characterization of the Intra-Unit-Cell magnetic order in Bi2Sr2CaCu2O8+d
• a-b anisotropy of the intra-unit-cell magnetic order in $\mathrm{YB}{\mathrm{a}}_2\mathrm{C}{\mathrm{u}}_3{\mathrm{O}}_{6.6}$
• Loop currents in quantum matter
• Tilted loop currents in cuprate superconductors
• Perspectives of the disproportionation driven superconductivity in strongly correlated 3d compounds
• Loop Currents in Two-leg Ladder Cuprates
• Investigation of potential fluctuating intra-unit cell magnetic order in cuprates by muon spin relaxation
• Topological structures in unconventional scenario for 2D cuprates
• Muon Spin Relaxation and fluctuating magnetism in the pseudogap phase of YBa${}_2$Cu${}_3$O${}_y$
• Charge and current orders in the spin-fermion model with overlapping hot spots
• Intra-unit-cell Magnetic Order in Stoichiometric La${}_2$CuO${}_4$