Far infrared Optical Studies of Monolayer WTe_{2 ­}at Ultralow Temperatures

Monolayer tungsten ditelluride (WTe2) has been established as a highly intriguing 2D material, which exhibits various topological and correlated quantum phases, such as the quantum spin Hall insulator, excitonic insulator, and gate-induced superconductivity. Yet theoretical understanding of this unique 2D crystal remains poorly developed, including even its basic band structure and the effects of electron correlations on it. In this talk we describe our efforts in probing its electronic phases using our newly developed instrument that integrates far-infrared optical spectroscopy with a dilution refrigerator. With optics, we hope to reveal new information about monolayer WTe2 that is hidden from electronic transport