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Interface‐Driven Structural Distortions and Composition Segregation in Two‐Dimensional Heterostructures
Author(s) -
Ditto Jeffrey,
Merrill Devin R.,
Mitchson Gavin,
Gabriel Joshua J.,
Mathew Kiran,
Hennig Richard G.,
Medlin Douglas L.,
Browning Nigel D.,
Johnson David C.
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201707270
Subject(s) - heterojunction , bilayer , materials science , monolayer , crystallography , alloy , chemical physics , layer (electronics) , composition (language) , condensed matter physics , nanotechnology , chemistry , optoelectronics , composite material , physics , membrane , biochemistry , linguistics , philosophy
The discovery of emergent phenomena in 2D materials has sparked substantial research efforts in the materials community. A significant experimental challenge for this field is exerting atomistic control over the structure and composition of the constituent 2D layers and understanding how the interactions between layers drive both structure and properties. While no segregation for single bilayers was observed, segregation of Pb to the surface of three bilayer thick PbSe–SnSe alloy layers was discovered within [(Pb x Sn 1− x Se) 1+δ ] n (TiSe 2 ) 1 heterostructures using electron microscopy. This segregation is thermodynamically favored to occur when Pb x Sn 1− x Se layers are interdigitated with TiSe 2 monolayers. DFT calculations indicate that the observed segregation depends on what is adjacent to the Pb x Sn 1− x Se layers. The interplay between interface‐ and volume‐free energies controls both the structure and composition of the constituent layers, which can be tuned using layer thickness.