Journal Article

IMPULSE-2026-00141

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Topological conical intersections govern proton transport in solids

Braun, A. (Corresponding author)

2026
Springer Berlin

Please use a persistent id in citations: doi:10.1557/s43577-026-01231-7

Abstract: A unified theoretical framework for proton transport in hydrated perovskite oxides, based on the concept of a protonic conical intersection (PCI) between two protonic diabatic states, is presented: a locally bound O–H configuration and a delocalized, conducting proton-polaron state. Vibronic coupling of these states to selected lattice coordinates generates a conical intersection that governs non-adiabatic proton transfer in the solid state. The PCI framework provides a coherent physical interpretation of key experimental phenomena observed across BaSnO3, BaZrO3, and BaCeO3, including hydration-induced Raman shifts, pronounced isotope effects between HO and DO, the emergence of soft and imaginary phonon modes under acceptor doping, and the conductivity maximum at intermediate Y concentrations. Within this picture, non-Arrhenius transport, entropy-enthalpy compensation, the Meyer–Neldel relationship, and the appearance of an isokinetic temperature arise naturally from the topology of the coupled proton-lattice energy landscape. More broadly, the protonic conical intersection establishes a conceptual bridge between non-adiabatic molecular physics and solid-state protonics, revealing that proton transport in functional oxides is governed by topological principles analogous to those controlling ultrafast electronic relaxation in polyatomic molecules.

Keyword(s): Basic research (1st) ; Chemistry (2nd) ; Condensed Matter Physics (2nd) ; Materials Science (2nd)

Note: ISSN 1938-1425 not unique: **2 hits**.

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Contributing Institute(s):

1. RESEDA (RESEDA)
2. E21 (E21)
3. Users (Users)

Experiment(s):

1. RESEDA: Resonance spin echo spectrometer (NL5S)

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Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Springer ; Essential Science Indicators ; IF >= 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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