Observing the anisotropic optical response of the heavy-fermion compound UNi2Al3

TL;DR

This study investigates the anisotropic optical response of the heavy-fermion compound UNi2Al3 using advanced THz spectroscopy, revealing temperature-dependent anisotropic conductivity that aligns with dc measurements.

Contribution

It extends infrared optical techniques to measure the anisotropic optical conductivity of UNi2Al3 in a new frequency range, providing insights into charge dynamics in heavy fermions.

Findings

Optical conductivity around 7cm^-1 is strongly temperature-dependent.

The optical response is anisotropic, differing parallel and perpendicular to the hexagonal planes.

Optical conductivity roughly follows the dc behavior.

Abstract

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 that - surprisingly - roughly follows the dc behavior.