Excited States Band Mapping and Ultrafast Nonequilibrium Dynamics in Topological Dirac Semimetal 1T-ZrTe$_2$

TL;DR

This study uses advanced photoemission microscopy to map excited states and analyze ultrafast electron dynamics in the topological Dirac semimetal 1T-ZrTe₂, revealing its electronic structure and relaxation mechanisms.

Contribution

It provides the first detailed excited state band mapping and ultrafast dynamics analysis of 1T-ZrTe₂, uncovering its Dirac cone dispersion and scattering processes.

Findings

Linear dispersion of Dirac cone above Fermi level uncovered

Multivalley electron-hole accumulation observed near Fermi level

Electron inverse lifetime depends linearly on binding energy

Abstract

We performed time- and polarization-resolved extreme ultraviolet momentum microscopy on topological Dirac semimetal candidate 1T-ZrTe$_2$. Excited states band mapping uncovers the previously inaccessible linear dispersion of the Dirac cone above the Fermi level. We study the orbital texture of bands using linear dichroism in photoelectron angular distributions. These observations provide hints on the topological character of 1T-ZrTe$_2$. Time-, energy- and momentum-resolved nonequilibrium carrier dynamics reveal that intra- and inter-band scattering processes play a capital role in the relaxation mechanism, leading to multivalley electron-hole accumulation near the Fermi level. We also show that electrons' inverse lifetime has a linear dependence on their binding energy. Our time- and polarization-resolved XUV photoemission results shed light on the excited state electronic structure of 1T-ZrTe$_2$ and provide valuable insights into the relatively unexplored field of quantum-state-resolved ultrafast dynamics in 3D topological Dirac semimetals.