Disentangling heterogeneity and disorder during ultrafast surface melting of orbital order

Understanding how light modifies long-range order is key to improve our ability to control material functionality on an ultrafast timescale. Transient spatial heterogeneity has been proposed in many materials, but isolating the dynamics of different regions experimentally has been challenging. Here...

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Published inarXiv.org
Main Authors Monti, Maurizio, Siddiqui, Khalid M, Perez-Salinas, Daniel, Agarwal, Naman, Bremholm, Martin, Li, Xiang, Prabhakaran, Dharmalingam, Liu, Xin, Babich, Danylo, Sander, Mathias, Deng, Yunpei, Lemke, Henrik T, Mankowsky, Roman, Liu, Xuerong, Wall, Simon E
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 03.07.2024
Subjects
Correlation
Heterogeneity
Long range order
Melting
Surface dynamics
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Summary:Understanding how light modifies long-range order is key to improve our ability to control material functionality on an ultrafast timescale. Transient spatial heterogeneity has been proposed in many materials, but isolating the dynamics of different regions experimentally has been challenging. Here we address this issue and measure the dynamics of orbital order melting in the layered manganite, La0.5Sr1.5MnO4, and isolate the surface dynamics from the bulk for the first time. Bulk measurements show orbital order is rapidly suppressed, but the correlation length surprisingly increases. However, the surface dynamics, show a stronger suppression and a significant decrease in correlation length. By isolating the surface changes, we find that light preferentially melts a less ordered surface and the loss of long-range order is likely driven by the formation of local and disordered polarons. Melting the disordered surface effectively increases the average correlation of the bulk probed volume, resolving the contradictory response. These results show that surface scattering methods are necessary to understand both surface and bulk dynamics in heterogeneous materials.
ISSN:2331-8422