In this paper we report a detailed analysis of the temperature-dependent optical properties of epitaxially grown cadmium arsenide (Cd3As2), a newly discovered three-dimensional Dirac semimetal. Dynamic Fermi level tuning -- instigated from Pauli-blocking in the linear Dirac cone -- and varying Drude response, generate large variations in the mid and far-infrared optical properties. We demonstrate thermo-optic shifts larger than those of traditional III-V semiconductors, which we attribute to the obtained large thermal expansion coefficient as revealed by first-principles calculations. Electron scattering rate, plasma frequency edge, Fermi level shift, optical conductivity, and electron effective mass analysis of Cd3As2 thin-films are quantified and discussed in detail. Our ab initio density functional study and experimental analysis of epitaxially grown Cd3As2 promise applications for nanophotonic and nanoelectronic devices, such as reconfigurable metamaterials and metasurfaces, nanoscale thermal emitters, and on-chip directional antennas.
@article{arxiv.1907.12105,
title = {Widely Tunable Optical and Thermal Properties of Dirac Semimetal Cd$_3$As$_2$},
author = {Hamid T. Chorsi and Shengying Yue and Prasad P. Iyer and Manik Goyal and Timo Schumann and Susanne Stemmer and Bolin Liao and Jon A. Schuller},
journal= {arXiv preprint arXiv:1907.12105},
year = {2020}
}