Characterization of Topological Quantum Materials by Terahertz-Time Domain Spectroscopy

New applications ranging from quantum computing to renewable energy are driven forward by the discovery and improvement of novel materials. To accomplish this, we use Terahertz-Time Domain Spectroscopy (THz-TDS), a non-destructive spectroscopic technique that is capable of probing the properties of delicate and sensitive samples through contactless measurements. THz-TDS uses sub-picosecond pulses of Terahertz radiation passed through the sample to obtain the material's complex-valued refractive index, from which many properties can be calculated, such as conductivity and material-specific "fingerprint" absorptions. In this presentation, we will focus on the characterization of ZrXY materials, a group of topological quantum materials (where X can be Ge or Si, and Y can be S, Se, or Te). Using THz-TDS to probe these materials at cryogenic temperatures will provide novel and unique insights into the materials' temperature-dependent electro-optical properties. For the growth of the ZrXY crystals, we are collaborating with the Hu research group at the University of Arkansas. Measurements on the ZrXY materials are still in progress, and our intent is to include preliminary results in this poster presentation. The poster will consist of an overview of the technique of THz-TDS, measurements of basic materials like GaAs, and preliminary results of the ZrXY materials.