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1. One-electron bonds in copper–aluminum and copper–gallium complexes

   https://doi.org/10.1039/D2SC01998A  

   Graziano, Brendan J.; Scott, Thais R.; Vollmer, Matthew V.; Dorantes, Michael J.; Young, Victor G.; Bill, Eckhard; Gagliardi, Laura; Lu, Connie C. (June 2022, Chemical Science)

   Odd-electron bonds have unique electronic structures and are often encountered as transiently stable, homonuclear species. In this study, a pair of copper complexes supported by Group 13 metalloligands, M[N(( o -C 6 H 4 )NCH 2 P i Pr 2 ) 3 ] (M = Al or Ga), featuring two-center/one-electron (2c/1e) σ-bonds were synthesized by one-electron reduction of the corresponding Cu( i ) ⇢ M(III) counterparts. The copper bimetallic complexes were investigated by X-ray diffraction, cyclic voltammetry, electron paramagnetic spectroscopy, and density functional theory calculations. The combined experimental and theoretical data corroborate that the unpaired spin is delocalized across Cu, M, and ancillary atoms, and the singly occupied molecular orbital (SOMO) corresponds to a σ-(Cu–M) bond involving the Cu 4p z and M n s/ n p z atomic orbitals. Collectively, the data suggest the covalent nature of these interactions, which represent the first examples of odd-electron σ-bonds for the heavier Group 13 elements Al and Ga. 

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2. Multiscale modeling of copper and copper/nickel nanofoams under compression

   https://doi.org/10.1016/j.commatsci.2019.109290  

   Ke, H.; Jimenez, A. Garcia; Da Silva, D.A. Rodrigues; Mastorakos, I. (February 2020, Computational Materials Science)
3. Atomistic Modeling of Interfacial Cracking in Copper-To-Copper Direct Bonding

   https://doi.org/10.1109/ECTC51687.2025.00207  

   Yang, Shengfeng; Lu, Jiali (May 2025, IEEE)

   Copper-to-copper (Cu-Cu) direct bonding is a crucial technology for high-density 3D integration in advanced semiconductor packaging, offering superior reliability over conventional solder-based approaches. However, void formation at the bonding interface remains a significant challenge, potentially compromising mechanical integrity. This study employs large-scale molecular dynamics (MD) simulations to investigate the atomic-scale mechanisms of void evolution in CuCu direct bonding under cyclic mechanical loading. Using polycrystalline Cu models with varying void distributions, grain size distributions, and interfacial bonding ratios, we examine how cyclic tensile loading influences void shrinkage and coalescence. Our results reveal that dislocation activity and grain growth near the bonding interface drive void elimination, with non-uniform void distributions promoting faster void coalescence, while evenly spaced voids shrink more gradually. Samples with a higher bonding ratio exhibit faster void reduction, though extended cyclic loading enhances void closure across all cases. These findings suggest that cyclic mechanical stress can be leveraged to improve bonding quality, offering insights into optimizing Cu−Cu bonding for high-density 3D integration systems. 

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4. Solution Depositions of Copper and Copper Sulfide Thin Films: Effects of Thiourea

   https://doi.org/10.1021/acs.jpcc.5c03002  

   Vienes, Jevalyne; Walker, Amy V (July 2025, The Journal of Physical Chemistry C)
5. Electromigration Study of Plasma Etched Copper Lines with Copper Oxide Capping Layers

   https://doi.org/10.1149/09703.0051ecst  

   Su, Jia Quan; Kuo, Yue (April 2020, ECS Transactions)