Berlin 2005 – scientific programme
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TT: Tiefe Temperaturen
TT 3: Correlated Electrons - Heavy Fermions
TT 3.4: Talk
Friday, March 4, 2005, 11:00–11:15, TU H3027
Drude Response of Heavy Fermions in UNi2Al3 — •Marc Scheffler1, Martin Dressel1, Martin Jourdan2, and Hermann Adrian2 — 11. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart — 2Institut für Physik, Universität Mainz, 55099 Mainz
The defining mass enhancement of the charge carriers in heavy-fermion compounds goes hand in hand with an equivalent decrease of the charge carrier relaxation rate. This relaxation rate can be identified from characteristics in the frequency-dependent conductivity: a roll-off in the real part σ1(ω) and a maximum in the imaginary part σ2(ω), two core predictions of the Drude model of metallic conduction.
Recently we succeeded with the first direct measurements of a Drude response in heavy-fermion UPd2Al3, revealing an extremely low relaxation rate in the GHz range. Now we present results on the related compound UNi2Al3 in the same frequency (45 MHz to 20 GHz) and temperature (1.65 K to 300 K) ranges. Again, at low temperatures we find a Drude behavior at GHz frequencies. Thus we can directly observe the relaxation rate as a function of temperature and use this to discuss the charge carrier density.