The Mid-Career Researcher Award recognizes exceptional achievements in materials research made by mid-career professionals.

Nicola Spaldin, ETH Zürich
Dynamical Multiferroicity
for creating a new theoretical framework describing multiferroics and for service to the materials community”  

An appealing mechanism for inducing multiferroicity in materials is the generation of electric polarization by a spatially varying magnetization that is coupled to the lattice through the spin-orbit interaction. Here we describe the reciprocal effect, in which a time-dependent electric polarization induces magnetization with no prerequisite of existing spin structures. We develop a formalism for this dynamical multiferroic effect for phonons that is feasible for computation from first principles. We show that the phonon Zeeman effect, which is the solid-state equivalent of the well-established vibrational Zeeman effect in molecules, derives straightforwardly from this theory. We further show that a recently observed behavior – the resonant excitation of a magnon by optically driven phonons – is described by the formalism. Finally, we illustrate examples that are not related to lattice dynamics and interpret the excitation of Dzyaloshinskii-Moriya electromagnons and the inverse Faraday effect from the viewpoint of dynamical multiferroicity.

Nicola Spaldin is the professor of materials theory at ETH Zürich. She is best known for her development of the class of materials known as multiferroics, which combine simultaneous ferromagnetism and ferroelectricity, for which she received the 2017 L'Oréal-UNESCO For Women in Science Award among many other honors. She is a passionate science educator, director of her department’s study program and holder of the ETH Golden Owl Award for excellence in teaching. When not trying to make a room-temperature superconductor, she can be found playing her clarinet, or skiing or climbing in the Alps.