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Department of Physics525 Northwestern Avenue
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Esmeralda Yitamben
Nanoscience and Technology Division, Argonne National Laboratory
"Engineering Chiral Quantum Corrals on Surfaces"
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Friday January 25, 2013
3:30pm PHYS 203
Refreshments are served at 3:00 p.m. in Physics room 242.
E. N. Yitamben
Nanoscience and Technology Division, Argonne National Laboratory, Argonne, IL 60439
Engineering molecular superstructures on metal surfaces opens great possibilities for the control and exploration of complex nano-systems for technological applications.
Of particular interest is the use of chiral molecules, such as alanine, and tryptophan, to build self-assembled nanoscale structures for the trapping of the two-dimensional free electron gas of a metal. Depending on the amino acid at hand, the reaction with the metallic surface is different. For alanine molecules, scanning tunneling microscopy, spectroscopy, and density functional theory (DFT) revealed the formation of a uniform network of hexagonal chiral pores, where each pore acts as a quantum corral by confining the two-dimensional electron gas of the Cu(111) surface state. Furthermore, each hexagonal pore acts as nanoscale tracks when excess alanine molecules were trapped at the inner perimeter of the pore, and were observed as rotating spatial states periodically moving between the six vertices of the hexagon. Contrary to this, Tryptophan molecules on Cu(111) cluster as chains to form a molecular labyrinth due to the presence of the indole group, which is a key component to tryptophan’s function as a precursor for transmitting signals to the brain.
Acknowledgements: This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357