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arXiv · 1912.07757

Loop Currents in Two-leg Ladder Cuprates

Dalila Bounoua·Lucile Mangin-Thro·Jaehong Jeong·Romuald Saint-Martin·Loreynne Pinsard-Gaudart·Yvan Sidis·Philippe Bourges
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Abstract

New phases with broken discrete Ising symmetries are uncovered in quantum materials with strong electronic correlations. The two-leg ladder cuprate \textbf{$Sr_{14-x}Ca_{x}Cu_{24}O_{41}$} hosts a very rich phase diagram where, upon hole doping, the system exhibits a spin liquid state ending to an intriguing ordered magnetic state at larger $Ca$ content. Using polarized neutron diffraction, we report here the existence of short range magnetism in this material for two $Ca$ contents, whose origin cannot be ascribed to Cu spins. This magnetism develops exclusively within the two-leg ladders with a diffraction pattern at forbidden Bragg scattering which is the hallmark of loop current-like magnetism breaking both time-reversal and parity symmetries. Our discovery shows local discrete symmetry breaking in a one dimensional spin liquid system as theoretically predicted. It further suggests that a loop current-like phase could trigger the long range magnetic order reported at larger doping in two-leg ladder cuprates.

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Dalila Bounoua, Lucile Mangin-Thro, Jaehong Jeong, Romuald Saint-Martin, Loreynne Pinsard-Gaudart, Yvan Sidis, Philippe Bourges. 2019-12-16. Loop Currents in Two-leg Ladder Cuprates. https://doi.org/10.1038/s42005-020-0388-1

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