Femtosecond to Nanosecond Lifetimes in Optically-Excited Nodal-Line Semimetals

Topological semimetals, such as the Dirac semimetal Cd₃As₂, have been proposed as superior materials for the next generation of highspeed optoelectronic devices due to their previously-observed ultrafast response times and high carrier concentrations [1]. Nodal-line semimetals, such as ZrSiS, should be even better suited to these applications because they have a much higher carrier concentration in Dirac bands, since those bands extend over lines or loops in k-space instead of just around a single point. In this talk, we will discuss our ultrafast optical measurements of the response of ZrSiX (X = S, Se, Te) to narrowband near-infrared pulses. Unlike other studies into this class of materials, multiple time scales are observed in the response, from the femtosecond- to nanosecond-scale. The spectral and kinetic features are connected to the structure and bandstructure of the materials, particularly surrounding the nodal-line straddling the Fermi level.


[1] Schoop, Pielnhofer, Lotsch, Chem. Mater. 2018, 30 (10), 3155-3176