0000000000667165
AUTHOR
N. Kasper
Correlation gap in the heavy-fermion antiferromagnetUPd2Al3
The optical properties of the heavy-fermion compound ${\mathrm{UPd}}_{2}{\mathrm{Al}}_{3}$ have been measured in a frequency range from 0.04 to 5 meV $(0.3--40{\mathrm{cm}}^{\ensuremath{-}1})$ at temperatures $2\mathrm{K}lTl300\mathrm{K}.$ Below the coherence temperature ${T}^{*}\ensuremath{\approx}50\mathrm{K},$ a hybridization gap opens around 10 meV. As the temperature decreases further $(Tl~20\mathrm{K}),$ a well-pronounced pseudogap of approximately 0.2 meV develops in the optical response; we relate this to the antiferromagnetic ordering which occurs below ${T}_{N}\ensuremath{\approx}14\mathrm{K}.$ The frequency-dependent mass and scattering rate give evidence that the enhancement of …
Nature of Heavy Quasiparticles in Magnetically Ordered Heavy FermionsUPd2Al3andUPt3
The optical conductivity of the heavy fermions $\mathrm{UPd}{}_{2}{\mathrm{Al}}_{3}$ and $\mathrm{UPt}{}_{3}$ has been measured in the energy range from 0.04 to 5 meV. In both compounds a well pronounced pseudogap of less than 1 meV develops in the optical response at low temperatures; we relate this to the antiferromagnetic ordering. From the energy dependence of the effective mass and scattering rate we conclude that the enhancement of the mass mainly occurs below the energy which is related to magnetic correlations between the local magnetic moments and the itinerant electrons. This implies that the magnetic order in these compounds is the prerequisite to the formation of the heavy quasi…