Supplemental Material
Spiral Patterns of Dislocations at Nodes in (111) Semi-coherent FCC Interfaces
Shuai Shao1, Jian Wang1,, Amit Misra2, Richard G. Hoagland1
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MST-8, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
MPA-CINT, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
Figure S1. Simulation cell showing mobile region that contains Cu atoms (orange) in the
upper crystal and Ni atoms (black) in the lower crystal, and the fixed region (brown).
The semi-fixed region acts as a fixed boundary during relaxation once the shear strain is
applied. The thickness of semi-fixed region in the y-direction is 1 nm (two times of the
cut-off distance of the interatomic potentials) for the two crystals [1]. Both crystals take
the same coordinate, x along [112̅], y along [111], and z along [11̅0].

Corresponding author: Dr. Jian Wang, Phone: +1 505 667 1238, E-mail: wangj6@lanl.gov
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Figure S2. The dependence of dislocation patterns on interface stacking fault energy. By
modifying the Cu-Ni cross-pair interaction, interfacial stacking fault energy (ISFE) was
varied from -17.6 mJ/m2 to 245 mJ/m2. It is evident that the areal ratio of fcc/hcp
increases as ISFE increases. Most importantly, the SP feature at nodes is evident in all
cases.
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Figure S3. The (111) low-angle twist boundaries in Cu, Al [2] and Ag [3]. The calculated
stacking fault energies are 45 mJ/m2 for Cu, 146 mJ/m2 for Al, and 18 mJ/m2 for Ag. The
twist angle θ =2˚. The distance between adjacent nodes is 7.3 nm in Cu, 8.2 nm in Al, and
8.3 nm in Ag, in consistence with the prediction according to Frank’s formula [4,5]. The
dislocations are mostly pure screw in nature and do not twist around the nodes.
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Figure S4. The Ag-Cu semi-coherent interface. Three pure edge Shockley partials
(orange lines) form in the interface. The interface dislocation lines are straight. The
distance between the adjacent nodes is 2.2 nm. (b) Atoms around the node experience the
displacements towards the center of the node, but no twisting around the node. Atoms are
colored according to the excess potential energy. Ag atoms are on the top.
References
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