Terahertz conductivity study of predicted Weyl semimetal Nd$_2$Ir$_2$O$_7$ and Eu$_2$Ir$_2$O$_7$ thin films
ORAL
Abstract
There is currently a growing interest in identifying materials with novel topological properties outside of the s- or p-orbital based bismuth chalcogenide topological insulators. One such proposal is the pyrochlore iridate materials $R_2$Ir$_2$O$_7$, where $R$ is a lanthanide series atom or yttrium. These have been predicted to be Weyl semimetals, containing exotic Fermi arc surface states and also an anomalous Hall effect. We have studied the temperature dependent terahertz conductivity of thin films of Nd$_2$Ir$_2$O$_7$ and Eu$_2$Ir$_2$O$_7$ grown by a novel off-axis sputtering technique. We find a close correspondence between DC transport properties and the extracted Drude parameters from fits to the THz conductivity. We will discuss these results in light of the predicted Weyl semimetal state of these materials.
*Work at OSU supported by the NSF MRSEC Center for Emergent Materials under grant DMR-1420451. Work at JHU supported by the Gordon and Betty Moore Foundation (GBMF2628).
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