Intrinsic vibrational angular momentum from non-adiabatic effects in non-collinear magnetic molecules

Abstract

We show that in non-collinear magnetic molecules, non-adiabatic (dynamical) effects due to the electron-vibron coupling are time-reversal symmetry breaking interactions for the vibrational field. As in these systems the electronic wavefunction can not be chosen as real, a nonzero geometric vector potential (Berry connection) arises. As a result, an intrinsic nonzero vibrational angular momentum occurs even for non-degenerate modes and in the absence of external probes. The vibronic modes can then be seen as elementary quantum particles carrying a sizeable angular momentum. As a proof of concept, we demonstrate the magnitude of this topological effect by performing non-adiabatic first principles calculations on platinum clusters and by showing that these molecules host sizeable intrinsic phonon angular momenta comparable to the orbital electronic ones in itinerant ferromagnets.

arXiv comment5 pages, 3 figures, to appear on Physical Review Letters

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• On the Meaning of Berry Force For Unrestricted Systems Treated With Mean-Field Electronic Structure
• Extrinsic Mechanisms of Phonon Magnetic Moment
• Magnons from time-dependent density-functional perturbation theory and nonempirical Hubbard functionals
• Electrically Controllable Chiral Phonons in Ferroelectric Materials
• Optically- and thermally-driven huge lattice orbital and spin angular momenta from spinning fullerenes
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• General ab initio framework for electronic-order-induced lattice-dynamics symmetry breaking
• Pseudo-chiral phonon splitting from octupolar magnetic order