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Topochemistry of Bowtie- and Star-Shaped Metal Dichalcogenide Nanoisland Formation
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posted on 2016-05-17, 00:00 authored by Vasilii I. Artyukhov, Zhili Hu, Zhuhua Zhang, Boris I. YakobsonA large number of experimental studies
over the past few years observed the formation of unusual highly symmetric
polycrystalline twinned nanoislands of transition metal dichalcogenides,
resembling bowties or stars. Here, we analyze their morphology in
terms of equilibrium and growth shapes. We propose a mechanism for
these complex shapes’ formation via collision of concurrently
growing islands and validate the theory with phase-field simulations
that demonstrate how highly symmetric structures can actually emerge
from arbitrary starting conditions. Finally, we use first-principles
calculations to propose an explanation of the predominance of high-symmetry
polycrystals with 60° lattice misorientation angles.