Athermal Fluctuations in Disordered Crystals

We analyze the fluctuations in particle positions and interparticle forces in disordered crystals composed of jammed soft particles in the limit of weak disorder. We demonstrate that such athermal systems are fundamentally different from their thermal counterparts, characterized by constrained fluct...

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Bibliographic Details
Published in:Physical review letters 2020-04, Vol.124 (16), p.168004-168004, Article 168004
Main Authors: Acharya, Pappu, Sengupta, Surajit, Chakraborty, Bulbul, Ramola, Kabir
Format: Article
Language:English
Subjects:
Computer simulation
Disks
Perturbation
Polydispersity
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Summary:We analyze the fluctuations in particle positions and interparticle forces in disordered crystals composed of jammed soft particles in the limit of weak disorder. We demonstrate that such athermal systems are fundamentally different from their thermal counterparts, characterized by constrained fluctuations of forces perpendicular to the lattice directions. We develop a disorder perturbation expansion in polydispersity about the crystalline state, which we use to derive exact results to linear order. We show that constrained fluctuations result as a consequence of local force balance conditions, and are characterized by non-Gaussian distributions, which we derive exactly. We analytically predict several properties of such systems, including the scaling of the average coordination with polydispersity and packing fraction, which we verify with numerical simulations using soft disks with one-sided harmonic interactions.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.124.168004