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arXiv · 2104.04294

Non-thermal breaking of magnetic order via photo-generated spin defects

Ernest Pastor·David Moreno-Mencía·Maurizio Monti·Allan S. Johnson·Nina Fleischmann·Cuixiang Wang·Youguo Shi·Xuerong Liu·Daniel G. Mazzone·Mark P. M. Dean·Simon Wall
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Abstract

In Mott insulators the evolution of antiferromagnetic order to superconducting or charge-density-wave-like states upon chemical doping underpins the control of quantum phases. Photo-doping can induce similar transitions on the ultrafast timescale, however the response of the spin system has remained elusive. Here, we use 4D-ultrafast optical spectroscopy to extract quantitative magnetic dynamics in the spin-orbit coupled Mott insulator Sr3Ir2O7. We demonstrate that light can non-thermally melt long-range spin order. At low fluences magnetic order recovers within 1 ps despite demagnetization of roughly 50%. However, high fluences induce a crossover to a long-lived demagnetized state without increasing the lattice temperature. We show that the generation of photo-induced spin defects enables a mechanism that stabilizes the demagnetized state which could help expose new transient phases.

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Ernest Pastor, David Moreno-Mencía, Maurizio Monti, Allan S. Johnson, Nina Fleischmann, Cuixiang Wang, Youguo Shi, Xuerong Liu, Daniel G. Mazzone, Mark P. M. Dean, Simon Wall. 2021-04-09. Non-thermal breaking of magnetic order via photo-generated spin defects. https://doi.org/10.1103/physrevb.105.064409

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