0000000000722789
AUTHOR
Julia P. Ostertag
Fabry-Perot resonances in birefringent YAlO_3 analyzed at terahertz frequencies
The optical conductivity of heavy fermions can reveal fundamental properties of the charge carrier dynamics in these strongly correlated electron systems. Here we extend the conventional techniques of infrared optics on heavy fermions by measuring the transmission and phase shift of THz radiation that passes through a thin film of UNi2Al3, a material with hexagonal crystal structure. We deduce the optical conductivity in a previously not accessible frequency range, and furthermore we resolve the anisotropy of the optical response (parallel and perpendicular to the hexagonal planes). At frequencies around 7cm^-1, we find a strongly temperature-dependent and anisotropic optical conductivity t…
Observing the anisotropic optical response of the heavy-fermion compound UNi2 Al3
The optical conductivity of heavy fermions can reveal fundamental properties of the charge carrier dynamics in these strongly correlated electron systems. Here we extend the conventional techniques of infrared optics on heavy fermions by measuring the transmission and phase shift of THz radiation that passes through a thin film of UNi 2 Al 3 , a material with hexagonal crystal structure. We deduce the optical conductivity in a previously not accessible frequency range, and furthermore we resolve the anisotropy of the optical response (parallel and perpendicular to the hexagonal planes). At frequencies around 7 cm -1 , we find a strongly temperature-dependent and anisotropic optical conducti…
Terahertz conductivity of the heavy-fermion compound UNi2Al3
We have studied the optical properties of the heavy-fermion compound UNi${}_{2}$Al${}_{3}$ at frequencies between 100 GHz and 1 THz (3 and 35 cm${}^{\ensuremath{-}1}$), temperatures between 2 and 300 K, and magnetic fields up to 7 T. From the measured transmission and phase shift of radiation passing through a thin film of UNi${}_{2}$Al${}_{3}$, we have directly determined the frequency dependence of the real and imaginary parts of the optical conductivity (or permittivity, respectively). At low temperatures the anisotropy of the optical conductivity along the $a$ and $c$ axes is about 1.5. The frequency dependence of the real part of the optical conductivity shows a maximum at low temperat…
Magnetoresistance and Phase Diagram of Thin-Film UNi2Al3
We study the dc resistivity of UNi2Al3 thin films as a function of temperature and magnetic field. We focus on the temperature range around the antiferromagnetic transition (TN \approx 4 K in zero applied field). From a clear signature of TN in the dc resistance along the crystallographic a-direction, we extract the shape of the magnetic phase diagram. Here we find quantitative differences in comparison to previous studies on bulk crystals.