Michael F. Crommie
Professor

Contact Address:
University of California at Berkeley
Department of Physics
366 Le Conte Hall #7300
Berkeley, CA 94720-7300

Office (361 Birge Hall):  (510) 642-9392
e-mail: crommie@socrates.berkeley.edu

Biography

Mike Crommie received a B.S. degree in physics from UCLA in 1984 and his Ph.D. from UC
Berkeley in 1991.  He was a post-doc at IBM Almaden for two years before becoming an Assistant
Professor in the Physics Dept. at Boston University in 1994.  He moved his laboratory to the
UC Berkeley Physics Deptartment in 1999 when he joined the faculty as an Associate Professor.
Awards and honors include a National Science Foundation Young Investigator Award (1994), the
AAAS Newcomb Cleveland Prize for 1993-94, and a Sloan Foundation Fellowship (1997).

Research Interests

Main research interest is in exploring the local electronic properties of atomic-scale structures at
surfaces.  Also interested in studying how local interactions between atomic-scale structures affect
the morphology and dynamics of mesoscopic systems.  The primary experimental tool is the ultra-high
vacuum cryogenic scanning tunnelling microscope, which can be used to both fabricate atomic-scale
structures and probe them spectroscopically.

Current Projects

Atomic manipulation:  The tip of a scanning tunneling microscope (STM) can be used to position individual
atoms and molecules on a conducting surface, allowing the fabrication of precise atomic-scale structures.
We have built a low temperature STM that is capable of performing atomic manipulation, and we are
currently exploring the physical parameters necessary to controllably position atoms and molecules on different
substrates. The ability to manipulate an atom depends on the relative strength of its coupling to the surface and
to the STM tip.  By characterizing these interactions we extend our ability to fabricate structures at the
atomic-scale, and further our understanding of how adsorbates bind to surfaces.

Visualizing low dimensional electronic behavior:  Electrons at some metal surfaces occupy a 2-dimensional
surface state, known as a Shockley state.  These electrons can be observed with an STM, allowing direct
visualization of the quantum mechanical state density of 2-dimensional electronic wavefunctions.  We are
currently studying such systems in an effort to better understand how 2-d electrons interact with adsorbates,
artificially fabricated atomic-scale structures, and surface reconstructions.

Magnetic nanostructures:  One of the smallest magnetic structures imaginable is a single magnetic atom in a
non-magnetic host.  If the host is a metal, then spin-flip scattering between conduction electrons and the
magnetic impurity leads to a many-body groundstate where an extended cloud of electrons screens the local
impurity moment.  This is known as the Kondo effect, and the influence of the "Kondo screening cloud" on
macroscopic material properties has been well studied.  We are currently using a low temperature STM to
directly investigate the local electronic properties of individual Kondo impurities at a clean metal surface.
We are using the atomic manipulation capabilities of our STM to probe magnetic interaction effects between
individual Kondo impurities and also to study artificially fabricated clusters of magnetic atoms.  These studies
help us to understand how the properties of microscopic magnetic structures evolve with the overall size
of a system.

Nanostructures on semiconductors:  Microfabricated circuit elements on semiconducting substrates form the
core of current high technology.  We are using a low temperature STM to probe the limits of atomic
manipulation on semiconducting surfaces.  Single atom manipulation on semiconductors holds the promise
of providing the ability to fabricate 1-dimensional wires only a single atom wide.  These structures are
predicted to exhibit novel electronic behavior, such as the Luttinger liquid groundstate.  Such studies bring
us closer to the goal of exploring electrical circuitry at the ultimate level of miniaturization.

Selected Publications

M. F. Crommie, C. P. Lutz, and D. M. Eigler, "Spectroscopy of a single adsorbed atom",
Phys. Rev. B 48 Rapid Communication, 2851 (1993).

M. F. Crommie, C. P. Lutz, and D. M. Eigler, "Imaging standing waves in a 2-dimensional electron gas",
Nature 363, 524 (1993).

M. F. Crommie, C. P. Lutz, and D. M. Eigler, "Confinement of electrons to quantum corrals on a metal
surface", Science 262, 218 (1993).

M. F. Crommie, C. P. Lutz, D. M. Eigler, and E. J. Heller, "Quantum Interference in 2-d Atomic-Scale
Structures", Surface Science 361/362, 864 (1996).

W. Chen, V. Madhavan, T. Jamneala, and M. F. Crommie, "STM observation of an electronic superlattice
at the surface of clean gold", Phys. Rev. Lett. 80, 1469 (1998).

V. Madhavan, W. Chen, T. Jamneala, M. F. Crommie, and N. S. Wingreen, "Tunneling into a Single
Magnetic Atom:  Spectroscopic Evidence of the Kondo Resonance", Science 280, 567 (1998).