Crystalline shielding mitigates structural rearrangement and localizes memory in jammed systems under oscillatory shear

Erin G Teich; K Lawrence Galloway; Paulo E Arratia; Danielle S Bassett

doi:10.1126/sciadv.abe3392

Crystalline shielding mitigates structural rearrangement and localizes memory in jammed systems under oscillatory shear

Sci Adv. 2021 May 12;7(20):eabe3392. doi: 10.1126/sciadv.abe3392. Print 2021 May.

Authors

Erin G Teich¹, K Lawrence Galloway², Paulo E Arratia^{2

3}, Danielle S Bassett^{4

5

6

7}

Affiliations

¹ Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
² Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
³ Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
⁴ Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA. dsb@seas.upenn.edu.
⁵ Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA.
⁶ Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
⁷ Santa Fe Institute, Santa Fe, NM 87501, USA.

Abstract

The nature of yield in amorphous materials under stress has yet to be fully elucidated. In particular, understanding how microscopic rearrangement gives rise to macroscopic structural and rheological signatures in disordered systems is vital for the prediction and characterization of yield and the study of how memory is stored in disordered materials. Here, we investigate the evolution of local structural homogeneity on an individual particle level in amorphous jammed two-dimensional (athermal) systems under oscillatory shear and relate this evolution to rearrangement, memory, and macroscale rheological measurements. We define the structural metric crystalline shielding, and show that it is predictive of rearrangement propensity and structural volatility of individual particles under shear. We use this metric to identify localized regions of the system in which the material's memory of its preparation is preserved. Our results contribute to a growing understanding of how local structure relates to dynamic response and memory in disordered systems.

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