Quantum Matter Seminar 21st July: "Resonant inelastic x-ray scattering studies of charge and spin dynamics in cuprate materials"

5 July 2023

This seminar is on the topic of RIXS as a means to study complex interactions in correlated electronic systems. It will be presented by Qisi Wang (Department of Physics, The Chinese University of Hong Kong)

Date: 21st July 2023, 2:00PM - 3:00PM

Location: 3.34, Physics Building

Abstract:

Resonant inelastic x-ray scattering (RIXS) has unique sensitivity to electronic correlations involving spin and charge degrees of freedom. In recent years, with the significant improvement of energy resolution, RIXS has become an important experimental technique to study the complex interactions in correlated electronic systems. In this talk, I will present our recent RIXS work on cuprate high-temperature superconductors and related systems. We first focus on the mechanism of charge ordering in the La-based system and demonstrate that electron-phonon coupling plays a significant role ^[1,2]. Tuning of the charge correlations is further realized by the application of uniaxial strain ^[3,4]. We also use RIXS to determine the magnon dispersions of different cuprate systems with exquisite precision, which allows us to extract the high-order exchange interactions. Combined with theoretical modelling, we found that strong quantum fluctuations in the weakly correlated Mott insulating cuprates can lead to the break-down of the antiferromagnetic Néel state ^[5]. This finding provides a new route to explore novel magnetic ground states in cuprate materials.

Further information

[1] Q. Wang et al., Phys. Rev. Lett. 124, 187002 (2020).

[2] Q. Wang et al., Sci. Adv. 7, eabg7394 (2021).

[3] Q. Wang et al., Nat. Commun. 13, 1795 (2022).

[4] J. Choi et al., Phys. Rev. Lett. 128, 207002 (2022).

[5] Q. Wang et al., unpublished.