CPM Seminar

Electron dynamics in quantum materials probed by advanced momentum-resolved spectroscopies

Fabio Boschini

INRS-EMT

Dynamic electron interactions are at the heart of the emergent phases of matter in quantum materials. During this talk I will review recent studies of quantum materials using time- and angle-resolved photoemission (TR-ARPES) and resonant inelastic x-ray scattering (RIXS) techniques.

TR-ARPES enables direct access to light-induced electron dynamics in solids. I will briefly review recent achievements of the TR-ARPES technique in the study of quantum materials [1]. Then, I will present the state-of-the-art TR-ARPES endstation and beamline at the Advanced Laser Light Source (ALLS) user facility at INRS-EMT, and I will discuss some preliminary results obtained on topological insulators and cuprate superconductors.

In addition, in Bi₂Sr₂CaCu₂O_8+δ (Bi2212), RIXS measurements found the existence of a quasi-circular pattern in the q_x-q_y plane at finite energies with the same wave vector magnitude as that of the observed static charge order peak [2]. However, it was not yet experimentally known whether this manifold extends to electron scattering at lower energies, in the quasi-elastic regime. I will present recent high-resolution RIXS measurements of Bi2212 where, by tracking the softening of the bond-stretching phonon, we revealed that dynamic correlations exist at energies below approximately 70 meV and are centered around a quasi-circular manifold in the q_x-q_y scattering plane [3]. I will end by discussing the possible implications of these quasi-circular dynamical correlations for the strange metal behavior in cuprates.

[1] Boschini, Zonno, Damascelli arXiv:2309.03935
[2] Boschini et al., Nat. Commun. 12, 597 (2021)
[3] Scott et al., Sci. Adv. 9, adg3710