Physical Society Colloquium

Bring On the Spin!

Don Eigler

IBM Almaden Research Center

While the greatest excitement surrounding the invention of the scanning tunneling microscope (STM) was about its atomic resolution imaging (pictures, after all, are sexy), it is often overlooked that one of the prime motivators for the creation of the STM was the desire to perform local spectroscopic measurements. It is perhaps not too surprising that spectroscopy has played second fiddle to imaging. When was the last time you were approached by someone who just had to show you the sexiest spectrum on the planet?

Local spectroscopic measurements with the STM are playing an increasingly important role in revealing the physics of nanometer scale systems. In this presentation I will discuss how we have extended the spectroscopic abilities of low temperature STMs to include the measurement of spin-excitation spectra. Utilizing spin-excitation spectroscopy as our primary tool, we are now capable of extracting exchange coupling energies and information on the spin configuration of nanometer-scale structures that we build to our own design. What we learn from these experiments will hopefully allow us to engineer the “energy landscape” of a system of spins in order to achieve nanometer-scale binary logic circuits that operate using only the spin degree of freedom.

Alluring (if not out-right sexy) spectra will be presented.

Work done in collaboration with Cyrus Hirjibehedin, Andreas Heinrich, Christopher Lutz, Jay Gupta, and Bruce Melior.