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Temporary Cohabitation : The Metastable Phase Au4Si

Hübner, Julia Maria LU ; Bierman, Brenna C. ; Wallenberg, Reine LU and Fredrickson, Daniel C. (2022) In Journal of the American Chemical Society 144(46). p.21016-21021
Abstract

The prediction, identification, and characterization of phases away from equilibrium conditions remain difficult challenges for material science. Herein, we demonstrate how systems whose phase diagrams contain deeply incising eutectics can offer opportunities to address these challenges. We report the synthesis of a new compound in the Au-Si system, a textbook example of a system with a deep eutectic. Au4Si crystallizes in a complex 18× 2×1 superstructure of the PtHg4type, based on the distortion of vertex-sharing Si@Au8cubes into bisdisphenoids. Au4Si decomposes upon heating and at room temperature even in high vacuum, highlighting its metastability. Electronic structure analysis reveals a... (More)

The prediction, identification, and characterization of phases away from equilibrium conditions remain difficult challenges for material science. Herein, we demonstrate how systems whose phase diagrams contain deeply incising eutectics can offer opportunities to address these challenges. We report the synthesis of a new compound in the Au-Si system, a textbook example of a system with a deep eutectic. Au4Si crystallizes in a complex 18× 2×1 superstructure of the PtHg4type, based on the distortion of vertex-sharing Si@Au8cubes into bisdisphenoids. Au4Si decomposes upon heating and at room temperature even in high vacuum, highlighting its metastability. Electronic structure analysis reveals a pseudogap at the Fermi energy, which is enhanced by the superstructure through the relief of Au-Au antibonding interactions. The pseudogap is associated with a Zintl-type bonding scheme, which can be extended to the locally ordered liquid. These results highlight the potential for metastable phases to form in deep eutectics that preserve the local structures of the liquid.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of the American Chemical Society
volume
144
issue
46
pages
6 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85142163337
  • pmid:36374186
ISSN
0002-7863
DOI
10.1021/jacs.2c10306
language
English
LU publication?
yes
id
903b42cf-b1d8-428c-9439-e2bcf439d60b
date added to LUP
2023-01-20 14:30:43
date last changed
2024-06-14 23:33:50
@article{903b42cf-b1d8-428c-9439-e2bcf439d60b,
  abstract     = {{<p>The prediction, identification, and characterization of phases away from equilibrium conditions remain difficult challenges for material science. Herein, we demonstrate how systems whose phase diagrams contain deeply incising eutectics can offer opportunities to address these challenges. We report the synthesis of a new compound in the Au-Si system, a textbook example of a system with a deep eutectic. Au<sub>4</sub>Si crystallizes in a complex 18× 2×1 superstructure of the PtHg<sub>4</sub>type, based on the distortion of vertex-sharing Si@Au<sub>8</sub>cubes into bisdisphenoids. Au<sub>4</sub>Si decomposes upon heating and at room temperature even in high vacuum, highlighting its metastability. Electronic structure analysis reveals a pseudogap at the Fermi energy, which is enhanced by the superstructure through the relief of Au-Au antibonding interactions. The pseudogap is associated with a Zintl-type bonding scheme, which can be extended to the locally ordered liquid. These results highlight the potential for metastable phases to form in deep eutectics that preserve the local structures of the liquid.</p>}},
  author       = {{Hübner, Julia Maria and Bierman, Brenna C. and Wallenberg, Reine and Fredrickson, Daniel C.}},
  issn         = {{0002-7863}},
  language     = {{eng}},
  number       = {{46}},
  pages        = {{21016--21021}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of the American Chemical Society}},
  title        = {{Temporary Cohabitation : The Metastable Phase Au<sub>4</sub>Si}},
  url          = {{http://dx.doi.org/10.1021/jacs.2c10306}},
  doi          = {{10.1021/jacs.2c10306}},
  volume       = {{144}},
  year         = {{2022}},
}