University of
California, Davis
Physics Department
Condensed Matter Seminar
**********************************
Dr. Zack Schlesinger
UC Santa Cruz
"Systematic Study of Kondo Resonance Scaling via
Infrared/Optical Spectroscopy"
The
Kondo resonance is a narrow many-body resonance (~density-of-states
peak) that
can arise at the Fermi level due to the interaction of localized
magnetic
moments with itinerant conduction electrons. This resonance
is
central to understanding the unusual low-temperature phenomena of
Kondo,
heavy fermion and mixed-valent systems, which include a resistivity
minimum and
enhanced specific heat. This talk will review aspects of Kondo
physics,
and present studies of the low-energy optical excitations associated
with the
Kondo resonance of the system YbIn(x)Ag(x)Cu4, in which a single hole
in the Yb
f-shell provides a relatively simple localized magnetic moment and
the
strength of the Kondo interaction can be systematically varied by varying x. We explore the scaling
behavior of the Kondo-resonance excitation and discuss our experimental
results
in the context of simple model calculations based on periodic Anderson
model
quasiparticle dispersion relations and scaling.
Thursday, June 3,
2004
4:10 p.m., 416 Phy/Geo