Information Transport and Computation in Nanometer-Scale Structures

Don Eigler, IBM Fellow, IBM Almaden Research Center

Abstract:

Information Transport and Computation in Nanometer-Scale Structures Don Eigler, IBM Fellow, IBM Almaden Research Center We discuss two examples of novel information transport and processing mechanisms in nanometer-scale structures. The local modulation and detection of a quantum state can be used for information transport at the nanometer length scale, an effect we call a "quantum mirage." Unlike conventional electronic information transport utilizing wires, the quantum mirage can be used to pass multiple channels of information through the same volume of a solid. We discuss a new class of nanometer-scale structures called "molecule cascades," and show how they may be used to implement a general-purpose binary-logic computer in which all of the circuitry is at the nanometer length scale. Work done in conjunction with Chris Lutz, Hari Manoharan, Mike Crommie, Andreas Heinrich, Jay Gupta and Bruce Melior.

Bio:

Don Eigler is a physicist at IBM's Almaden Research Center in San Jose, California, where he has been the leader of the Low-Temperature Scanning Tunneling Microscopy Project. His group's research is aimed at understanding the physics of nanometer-scale structures and exploring the applications of nanometer-scale structures to computing. In 1989 Don demonstrated the ability to manipulate individual atoms with a low-temperature scanning tunneling microscope, spelling out "I-B-M" with individual xenon atoms. Since then, his group's results include the invention of "quantum corrals," discovery of the "quantum mirage" effect, demonstration of a fundamentally new way to transport information through a solid, the demonstration of nanometer-scale logic circuits based on Molecular Cascades, and demonstration of single-atom spin-flip spectroscopy. Don received both his bachelors and doctorate degrees from the University of California San Diego and was named its Outstanding Alumnus of the year in 1999. Don has been recognized for his accomplishments with the Davisson-Germer Prize, the Dannie Heineman Prize, the Newcomb-Cleveland Prize, the Grand Award for Science and Technology, the Nanoscience Prize, and numerous honorary lectureships. In 2002 he received an honorary doctorate from the Technical University of Delft. He is a fellow of the American Physical Society and the American Association for the Advancement of Science, and in 2004 was elected a member of the Max Planck Society. He was named an IBM Fellow in 1993, the highest technical honor in the IBM Corporation.

Host: Sotiris Masmanidis

Companion Tutorial: Spin-Coupled Chains Assembled with Atomic Precision

Tuesday, January 31, 2006

10:00 am - 11:00 am, Beckman Institute Auditorium

Cyrus F. Hirjibehedin, IBM Almaden Research Center

Abstract:

Magnetic nanostructures are increasing data storage capacities and are promising candidates for implementations of novel spin-based computation techniques. The relative simplicity and reduced dimensionality of nanoscale magnetic structures also make them attractive model systems for studying the interactions between small numbers of quantum spins. Using a high-field low-temperature scanning tunneling microscope, we assemble linear chains of Mn atoms one atom at a time on thin, insulating layers of copper nitride. We probe the excitation spectra of the individual magnetically-coupled chains with inelastic electron tunneling spectroscopy. The spectra change dramatically with both the parity and length of the chain and reveal a variety of spin excitations. These results provide direct evidence of antiferromagnetic coupling between the atomic spins on neighboring Mn atoms. A quantitative comparison with the Heisenberg open chain model allows us to measure the coupling strength ~6meV between these atomic spins. We further determine the spin of each Mn atom on the surface to be 5/2.

Bio:

Cyrus F. Hirjibehedin is a postdoctoral Research Staff Member at IBM's Almaden Reseach Center in San Jose, California. His research is focused on the physics of nanometer-scale structures and the application of nanometer-scale structures in information technology.

Cyrus received a B.S. in both Physics and Computer Science from Stanford University in 1997, after which he earned a Ph.D. in Physics from Columbia University in 2004. His dissertation research, conducted at Columbia and Bell Labs, Lucent Technologies, under the guidance of Professor Aron Pinczuk, was a study of novel correlation effects in low dimensional electron systems formed in semiconductor quantum structures.

Cyrus is currently a member of the Almaden Research Center's Low-Temperature Scanning Tunneling Microscopy Group. Working with Andreas Heinrich and Don Eigler, he is using the atom-manipulation and spin-excitation-spectroscopy capabilities of a low-temperature high-field scanning tunneling microscope to study the onset of cooperative magnetic behavior in atomically-precise low-dimensional structures.