The project NirvAna aims to evidence anapoles (or polar toroidic dipoles) in condensed matter physics and more particularly in high temperature copper oxide superconductors. A spontaneous circulating loop current state, belonging to the anapole class, has been proposed to be the driving force controlling the physics of these materials. Using polarized neutron diffraction, we have already discovered a novel magnetic state in their most mysterious electronic state, the so-called “pseudo-gap phase”. It is broadly debated among the community that understanding the origin of the “pseudo-gap phase” would uncover the mystery of the high temperature superconductivity in copper oxide materials.
We wish now to study whether the observed order corresponds to the orbital magnetic moments generated by the spontaneous microscopic loop currents described above. We propose to build an accurate polarized neutron diffraction setup: we will be able to perform experiments to resolve the magnetic structure factor of the novel magnetic order in various cuprates to highlight these anapoles.
The project will also address the fundamental issue of the mechanism of high-temperature superconductivity of copper oxides, which remains so far still unsolved. Indeed, it is argued that superconductivity would emerge from such a novel state where associated low energy fluctuations will provide the glue for Cooper superconducting pairs. We propose to develop more powerful inelastic polarized neutron scattering measurements to evidence the quantum critical fluctuations, responsible in this approach for the high temperature superconductivity.
The NirvAna project will identify anapoles in condensed matter as well as a novel mechanism for high temperature superconductivity. A final outcome of this proposal is to find out other systems with strong electronic correlations where similar novel electronic states might occur.
Monsieur Philippe BOURGES (Laboratoire Léon Brillouin)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
LLB-CEA-CNRS Laboratoire Léon Brillouin
Help of the ANR 592,048 euros
Beginning and duration of the scientific project: December 2015 - 48 Months