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Modeling impurity-assisted chain creation in noble-metal break junctions
S Di Napoli1, A Thiess, S Blügel
1Departamento de Física de la Materia Condensada, CAC-CNEA, Avenida General Paz 1499, (1650) San Martín, Pcia. de Buenos Aires, Argentina. dinapoli@tandar.cnea.gov.ar
Summary
This study extends a model for metal chain formation in break junctions to include impurities. Impurities like hydrogen, carbon, oxygen, and nitrogen significantly enhance the probability of forming stable copper, silver, and gold chains.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Surface Science
Background:
- Break junction experiments are crucial for studying atomic-scale conductivity.
- Previous models focused on perfect atomic chains.
- Impurities are common in break junction experiments and can influence chain stability.
Purpose of the Study:
- To generalize a model for atomic chain formation to include impurities.
- To investigate the impact of s and p impurities on noble-metal chains (Cu, Ag, Au).
- To study the producibility trends of these chains with adatoms (H, C, O, N).
Main Methods:
- Generalization of the Thiess et al. (2008) model for chain formation.
- Application of the extended model to zigzag transition-metal chains.
- Utilizing full-potential linearized augmented plane-wave (FP-LAPW) first-principles calculations for material-specific parameters.
Main Results:
- Impurities significantly affect the binding properties of noble-metal chains.
- Impurity-induced bond strengthening enhances chain formation probability.
- Formation of zigzag bonds due to impurities also increases chain stability.
Conclusions:
- The presence of impurities is critical for understanding noble-metal chain formation in break junctions.
- The generalized model accurately predicts enhanced chain formation with impurities.
- This work provides insights into controlling and predicting atomic chain stability in nanoscale devices.
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