Year: 2023
Type: preprint
Abstract: The underlying dielectric properties of materials, intertwined with intriguing phenomena such as topological polariton modes and anisotropic thermal conductivities, stem from the anisotropy in atomic vibrations. Conventionally, X-ray diffraction techniques have been employed to estimate thermal ellipsoids of distinct elements, albeit lacking the desired spatial and energy resolutions. Here we introduce a novel approach utilizing the dark-field monochromated electron energy-loss spectroscopy for momentum-selective vibrational spectroscopy, enabling the cartographic delineation of variations of phonon polarization vectors. By applying this technique to centrosymmetric cubic-phase strontium titanate, we successfully discern two types of oxygen atoms exhibiting contrasting vibrational anisotropies below and above 60 meV due to their frequency-linked thermal ellipsoids. This method establishes a new pathway to visualize phonon eigenvectors at specific crystalline sites for diverse elements, thus delving into uncharted realms of dielectric, optical, and thermal property investigations with unprecedented spatial resolutions.
Source: arXiv (Cornell University)
Language: English
Subfield: Structural Biology
Domain: Life Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, UC Irvine Materials Research Institute, National Science Council, Knut och Alice Wallenbergs Stiftelse, Vetenskapsrådet, University of California, Santa Barbara, University of California, Irvine, Division of Materials Research, Basic Energy Sciences, Division of Materials Sciences and Engineering
Awards: G1135980590, G1441096865, UCI MRSEC: Materials Discovery Through Atomic Level Structural Design and Charge Control, G2593733834, G3321450376, G3631573628, G4228951661, STRUCTURE AND DYNAMICS OF DOMAINS IN FERROELECTRIC NANOSTRUCTURES - IN SITU TEM STUDIES, G712881263, G796431723, G832629528, NAISS, G97908232
OpenAlex ID: W4389364015