Charge Density Wave Materials Probed in Time and Momentum Space

Charge density wave phenomena involving periodic electronic charge order in solids are common in low dimensional quantum-materials. They arise from a delicate balance of electron-electron and electron-phonon interactions. The interest in understanding these systems comes from the associated metal to insulator transitions with potential applications in switching devices and memristors. In this talk, I will present our recent research efforts in offering an accurate description of the electronic structure. In particular, combining angle resolved photoemission spectroscopy and band structure T-TaSe2 [1,2]. In addition, by performing experiments with time resolution <100 fs, I will explain how coherent phonon oscillations seen in the band structure allow for an estimation of the anharmonic potential characterizing the amplitude mode of the CDW condensate [3]. The results are a step forward in the understanding of CDW physics in TaSe2 compounds and towards establishing time- and momentum-resolved photoemission as valuable methods for quantum materials.

[1] Sayers, C. J.; Hedayat, H.; Ceraso, A.; Museur, F.; Cattelan, M.; Hart, L. S.; Farrar, L. S.; Dal Conte, S.; Cerullo, G.; Dallera, C.; et al. Phys. Rev. B 2020, 102 (16), 161105.
[2] Sayers, C.Phys. Rev. Lett. 2023, 130 (15), 156401.