AVS 60th International Symposium and Exhibition
    Nanometer-scale Science and Technology Wednesday Sessions
       Session NS+AS+BI+SP-WeM

Paper NS+AS+BI+SP-WeM6
Amino Acid Immobilization and Surface Diffusion of Copper

Wednesday, October 30, 2013, 9:40 am, Room 203 B

Session: Nanoscale Imaging and Microscopy
Presenter: A.J. Mannix, Northwestern University
Authors: E. Iski, University of Tulsa
A.J. Mannix, Northwestern University
B.T. Kiraly, Northwestern University
M.C. Hersam, Northwestern University
N.P. Guisinger, Argonne National Laboratory
Correspondent: Click to Email
The 2D-scale study of relevant biomolecules, like amino acids, is pertinent for a variety of applications from the origin of biological homochirality and the amplification of surface chirality to the examination of noncovalent supramolecular interactions. Importantly, the study of these molecules on a copper surface may also be significant to the medical community as the binding of amino acids/proteins to copper ions plays a major role in the development of neurodegenerative diseases, like Mad Cow’s Disease and Alzheimer’s. The need for pristine molecular resolution of these systems requires the use of ultra-high vacuum scanning tunneling microscopy (UHV STM) as the primary technique for these studies. Through the detailed examination of the self-assembly behavior of five amino acid molecules on a Cu(111) single crystal, a fascinating and unexpected phenomenon was discovered. All of the amino acids assisted in the immobilization of copper atoms on the surface. The energetic landscape of the surface as mediated by temperature and molecular coverage facilitated the growth of copper islands and clusters. The growth and size fluctuation of the islands offered an interesting snapshot of metal nanocluster diffusion that often occurs at time scales beyond the resolution of a given surface science technique. The presence of ~1 ML of molecules on the surface effectively trapped the metal atoms into localized islands. Elevated temperatures (≤ 350 K) were used to promote further diffusion, coalescence, and extinction of the islands for a more detailed understanding of the coarsening and ripening mechanisms. In conclusion, while these systems provide insights into the chiral assembly of amino acids on Cu(111), they also provide a unique glimpse into metal surface diffusion and offer the ability to study the mass transport of metal atoms, which is important for the understanding of thin film growth and its morphological evolution.