High-resolution time- and angle-resolved photoemission studies on quantum materials

Abstract

Upon femtosecond laser excitation in quantum materials, it is possible to study the many-body interactions through the non-equilibrium processes, realize ultrafast electronic phase transitions, and achieve photoinduced novel states or hidden states. Such studies of the interaction between the ultrafast laser and the quantum materials are the frontiers and attract significant research interests in the field of condensed matter physics. Time- and angle-resolved photoemission spectroscopy is a key experimental tool to study the ultrafast electronic dynamics in quantum materials after photoexcitation. This paper reviews the development of a high-resolution time- and angle-resolved photoemission system based on nonlinear optical crystals and the studies on the ultrafast electronic dynamics in quantum materials using such a setup, including (1) probing the unoccupied electronic states in quantum materials, (2) photoinduced ultrafast electronic phase transitions, and (3) photoinduced new states of matter.

Aspects of symmetry and topology in the charge density wave phase of 1T–TiSe2

“…Time resolution was achieved by varying the delay between the pump and probe pulses. The overall energy and time resolutions were optimized to 16 meV and 113 fs, respectively [36]. High-quality single crystals of 1T-TiSe 2 were grown by chemical vapor transport with an iodine transport agent at grown temperature 650 • C, and the sample was cleaved in an ultrahigh vacuum condition with a base pressure better than 3× 10 −11 Torr.…”

Optical manipulation of the topological phase in ZrTe5 revealed by time- and angle-resolved photoemission

“…The TRARPES experiments were performed on a homebuilt TRARPES system [44,45] using a 1.77-eV infrared laser as the pump beam and a 6.05-eV ultraviolet laser as the probe beam. The measurements were conducted with a repetition rate of 250 kHz, and the spot sizes on the sample of the pump and probe beams were approximately 90 µm and 23 µm, respectively.…”