Ultrafast relaxation of acoustic and optical phonons in a topological nodal-line semimetal ZrSiS

Abstract

Topological nodal line semimetals are characterised by band crossings along a line, or closed loop inside, of the Brillouin zone and belong to a larger family of topological semimetals. Here, using time-resolved angle resolved photoemission spectroscopy, the authors investigate the ultrafast relaxation dynamics in the bulk nodal line state of one such material, ZrSiS, elucidating the role of optical and acoustic phonon cooling.