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arXiv · 2403.13070

Ultrafast pseudomagnetic fields from electron-nuclear quantum geometry

Lennart Klebl·Arne Schobert·Martin Eckstein·Giorgio Sangiovanni·Alexander V. Balatsky·Tim O. Wehling
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Abstract

Recent experiments demonstrate precise control over coherently excited circular phonon modes using high-intensity terahertz lasers, opening new pathways towards dynamical, ultrafast design of magnetism in functional materials. While the phonon Zeeman effect enables a theoretical description of phonon-induced magnetism, it lacks efficient angular momentum transfer from the phonon to the electron sector. In this work, we put forward a coupling mechanism based on electron-nuclear quantum geometry, with the inverse Faraday effect as a limiting case. This effect is rooted in the phase accumulation of the electronic wavefunction under a circular evolution of nuclear coordinates. An excitation pulse then induces a transient level splitting between electronic orbitals that carry angular momentum. First-principle simulations on SrTiO$_3$ demonstrate that in parts of the Brillouin zone, this splitting between orbitals carrying angular momentum can easily reach 50 meV.

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Lennart Klebl, Arne Schobert, Martin Eckstein, Giorgio Sangiovanni, Alexander V. Balatsky, Tim O. Wehling. 2024-03-19. Ultrafast pseudomagnetic fields from electron-nuclear quantum geometry. https://doi.org/10.1103/physrevlett.134.016705

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