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5–6 Dec 2024
Munich Marriott Hotel
Europe/Berlin timezone

Understanding the mechanisms of hydrogen induced modifications in correlated oxides.

5 Dec 2024, 17:35
25m
Marriott

Marriott

Talk (20 min + 5 min discussion) Quantum Phenomena Quantum Phenomena

Speaker

Laura Guasco

Description

Correlated oxides are the ideal platform for hydrogen induced structural and electronic modifications, due to the presence of high amount of oxygen, a quite flexible crystal structure and the delicate balance between structural and electronic degrees of freedom. A striking example are the nickelates, for which hydrogen can induce metal to insulator transitions [1], superconductivity [2], and colossal lattice expansion [3]. The mechanisms of interaction between hydrogen and the oxide is often not fully understood, due to the difficult detection of hydrogen in thin films. Neutron reflectometry (NR), in combination with x-ray scattering and other complementary techniques, can be a powerful tool for non-destructive, in situ, non-local characterization of such systems. Here we report on the specific case of LaNiO$_{3}$ which exhibits an intermediate insulating state followed by re-entrant metallicity accompanied by colossal expansion during hydrogen exposure. Via in situ NR we measured time-dependent hydrogen and oxygen content in the layer during reaction with H$_{2}$. By combining the stoichiometry obtained from NR with the x-ray diffraction and absorption spectra at various stages of reaction we propose a full reaction mechanism to explain the electronic phase changes observed.

References
[1] J. Shi, Y. Zhou, S. Ramanathan, Nat. Commun. 2014, 5, 4860.
[2] Ding, X., Tam, C.C., Sui, X. et al. Nature 615, 50–55 (2023).
[3] Haowen Chen, et al. Nano Letters 2022 22 (22), 8983-8990

Primary authors

Co-authors

Prof. Bernhard Keimer (MPI-FKF) Dr David Cortie (ANSTO) Eberhard Goering (MPI-FKF) Eva Benckiser (MPI-FKF) Dr Lars Bannenberg (TU Delft) Peter Wochner (MPI-FKF) Thomas Keller (MPI for Solid State Research, Stuttgart)

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