title: Self-assembly of magnetite nanocubes into helical superstructures.
abstract: Organizing inorganic nanocrystals into complex architectures is challenging and typically relies on preexisting templates, such as properly folded DNA or polypeptide chains. We found that under carefully controlled conditions, cubic nanocrystals of magnetite self-assemble into arrays of helical superstructures in a template-free manner with >99% yield. Computer simulations revealed that the formation of helices is determined by the interplay of van der Waals and magnetic dipole-dipole interactions, Zeeman coupling, and entropic forces and can be attributed to spontaneous formation of chiral nanocube clusters. Neighboring helices within their densely packed ensembles tended to adopt the same handedness in order to maximize packing, thus revealing a novel mechanism of symmetry breaking and chirality amplification.
authors: Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
authors: Gurvinder
authors: G
authors: Singh
authors: Department of Chemistry, University of Illinois, Chicago, IL 60607, USA.
authors: Henry
authors: H
authors: Chan
authors: Department of Chemistry, University of Illinois, Chicago, IL 60607, USA.
authors: Artem
authors: A
authors: Baskin
authors: Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
authors: Elijah
authors: E
authors: Gelman
authors: Department of Chemistry, University of Illinois, Chicago, IL 60607, USA.
authors: Nikita
authors: N
authors: Repnin
authors: Department of Chemistry, University of Illinois, Chicago, IL 60607, USA. Department of Physics, University of Illinois, Chicago, IL 60607, USA. rafal.klajn@weizmann.ac.il pkral@uic.edu.
authors: Petr
authors: P
authors: Král
authors: Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel. rafal.klajn@weizmann.ac.il pkral@uic.edu.
authors: Rafal
authors: R
authors: Klajn