Reversible structure manipulation by tuning carrier concentration in metastable Cu2S

by Tao, Jing; Chen, Jingyi; Li, Jun; Mathurin, Leanne Elizabeth; Zheng, Jin-Cheng; Li, Yan; Lu, Deyu; Cao, Yue; Wu, Lijun; Cava, Robert Joseph; Zhu, Yimei

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The optimal functionalities of materials often appear at phase transitions involving simultaneous changes in the electronic structure and the symmetry of the underlying lattice. It is experimentally challenging to disentangle which of the two effects-electronic or structural-is the driving force for the phase transition and to use the mechanism to control material properties. Here we report the concurrent pumping and probing of Cu2S nanoplates using an electron beam to directly manipulate the transition between two phases with distinctly different crystal symmetries and charge-carrier concentrations, and show that the transition is the result of charge generation for one phase and charge depletion for the other. We demonstrate that this manipulation is fully reversible and nonthermal in nature. Our observations reveal a phase-transition pathway in materials, where electron-induced changes in the electronic structure can lead to a macroscopic reconstruction of the crystal structure.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Volume
114
Issue
37
Year
2017
Start Page
9832
ISBN/ISSN
0027-8424
PMID
28855335
DOI
10.1073/pnas.1709163114