Multi‐Step Crystallization of Self‐Organized Spiral Eutectics
Abstract
A method for the solidification of metallic alloys involving spiral self‐organization is presented as a new strategy for producing large‐area chiral patterns with emergent structural and optical properties, with attention to the underlying mechanism and dynamics. This study reports the discovery of a new growth mode for metastable, two‐phase spiral patterns from a liquid metal. Crystallization proceeds via a non‐classical, two‐step pathway consisting of the initial formation of a polytetrahedral seed crystal, followed by ordering of two solid phases that nucleate heterogeneously on the seed and grow in a strongly coupled fashion. Crystallographic defects within the seed provide a template for spiral self‐organization. These observations demonstrate the ubiquity of defect‐mediated growth in multi‐phase materials and establish a pathway toward bottom‐up synthesis of chiral materials with an inter‐phase spacing comparable to the wavelength of infrared light. Given that liquids often possess polytetrahedral short‐range order, our results are applicable to many systems undergoing multi‐step crystallization.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 23, 2020
- Source ID
- 10.1002/smll.201906146
Entities
People
- Ashwin J. Shahani
- Hrishikesh Bale
- J. R. Gao
- Kai Sun
- Robert O. Ritchie
- Saman Moniri
- Tianxiang Lu
- Tobias Volkenandt
- Yeqing Wang
Organizations
- Air Force Office of Scientific Research
- Argonne National Laboratory
- National Science Foundation
- Northeastern University
- University of California
- University of Michigan