Project Details
Phonon and magnon velocities, lifetimes, and band-topology largely determine energy transport in solids. Through mutual interactions and interactions with charge carriers, emergent phenomena based on hybridizing collective lattice and spin excitations can appear. Understanding these phenomena challenges conventional lattice- and spin-dynamics models and requires detailed description of, e.g., electron-phonon and magnon-phonon couplings. Thus, the overarching goal of this project is to understand hybridization mechanisms of atomic vibrational and spin excitations in energy materials in order to control energy transport and functionalities. To achieve this goal, this proposed work addresses three scientific aims: (1) Unveil how lattice non-linearity, incommensurability, and hybridization with molecular modes control heat and charge propagation, (2) Understand how spin structure and transport is controlled by disorder and lattice coupling, and (3) Determine constraints from lattice topology and quantum fluctuations on thermal transport and ferroic order. To elucidate these topics, neutron scattering will
be integrated with response theory modelling to guide predictive design of new materials with tailored thermal and magnetic transport and quantum ferroic properties. Conventional inelastic neutron scattering struggles to separate magnon and phonon contributions and determine phonon lifetimes with sufficient energy resolution. Thus, we will develop and utilize novel neutron spin-polarization and -precession techniques to separate spin and lattice contributions and enhance energy resolution, respectively. These advances will yield critical inputs for transport and phase-stability modeling. The novel atomic-scale understanding of lattice and spin hybridization phenomena will strongly contribute to DOE’s mission towards novel emerging materials for energy transport and conversion, and quantum information science.
