Past colloquia and seminars


Strain as a new tuning parameter in angle resolved photoemission experiments of quantum materials

General public Colloquium / Congress / Forum
31.10.2018 17:15 - 18:15

In this talk I will discuss recent angle resolved photoemission (ARPES) experiments on Ca2RuO4 under uniaxial strain. External tuning parameters such as magnetic fields, pressure and strain play a key role in the study of quantum materials [1]. Yet combining them with direct measurements of the electronic structure by ARPES proved challenging.
Using ultrathin plate-like crystals mounted on a bending-type strain apparatus, we recently succeeded in driving the archetypal multiband Mott system Ca2RuO4 across the metal-insulator transition, while monitoring the evolution of its electronic structure by ARPES [2]. Our measurements show that metallicity emerges from a marked redistribution of charge within the Ru t2g shell, accompanied by a sudden collapse of the spectral weight in the lower Hubbard band and the emergence of a well-defined Fermi surface. In the metallic state, we find a substantial enhancement of the spin-orbit interaction over its atomic value. I will briefly discuss the relevance of these findings for other correlated systems as well as new opportunities opened by combining quasi-continuous strain-tuning with direct electronic structure measurements.

[1] C. Hicks et al., Science 355, eaaf9398 (2017)
[2] S. Riccò et al. arXiv:1803.00488 (2018)

When? 31.10.2018 17:15 - 18:15
Where? PER 08 0.51
Chemin du Musée 3
1700 Fribourg
speaker F. Baumberger, DQMP University of Geneva & Swiss Light Source, PSI
Contact Prof. Claude Monney
Monney Claude
Chemin du Musée 3
1700 Fribourg
026 300 91 63 3