Excited State Band Mapping and Ultrafast Nonequilibrium\nDynamics in Topological Dirac Semimetal 1T-ZrTe<sub>2</sub>

We performed time-\nand polarization-resolved extreme ultraviolet\nmomentum microscopy on the topological Dirac semimetal candidate 1T-ZrTe<sub>2</sub>. Excited state band mapping uncovers the previously inaccessible\nlinear dispersion of the Dirac cone above the Fermi level. We study\nthe orbital texture of bands using linear dichroism in photoelectron\nangular distributions. These observations provide hints about the\ntopological character of 1T-ZrTe<sub>2</sub>. Time-, energy-, and\nmomentum-resolved nonequilibrium carrier dynamics reveal that intra-\nand interband scattering processes play a major role in the relaxation\nmechanism, leading to multivalley electron–hole accumulation\nnear the Fermi level. We also show that electrons’ inverse\nlifetime has a linear dependence as a function of their excess energy.\nOur time- and polarization-resolved XUV photoemission results shed\nlight on the excited state electronic structure of 1T-ZrTe<sub>2</sub> and provide valuable insights into the relatively unexplored field\nof quantum-state-resolved ultrafast dynamics in 3D topological Dirac\nsemimetals.