Dr. Edwin Fohtung, LANSCE Associate Professor at New Mexico State University and faculty at the Department of Physics received a new grant from the Department of Defense (DOD), Airforce Office of Scientific Research (AFOSR). The three-year $396 K grant funded by the DOD-AFOSR is entitled “Nanoscale Probing of Magneto-electric Phases.”
This project deals with the application of nanoscale topological defect engineering concepts and in-operando 3D coherent X-ray scattering and imaging techniques, pioneered by Professor Fohtung, to the development of the next generation of magneto-electric devices that enable advanced electro-optic detection, storage, sensing, and imaging.
The main idea of the approach is tuning quantum states of topological defect relics such as quantum vortices and topological strings to achieve phonon-magnon energy dispersion in device nanostructured materials for achieving optimum electron-phonon, electron – magnon, phonon-polariton scattering rates, and a corresponding improvement in the device performance. Phonons are the quanta of the crystal lattice vibrations that scatter electrons and conduct heat while polaritons are hybrid particles made up of a photon strongly coupled to an electric dipole. In insulating oxides such as ferroelectrics and multiferroics, phonons could be hard or soft. In the disordered-to-ordered magneto-electric phases there exists a certain unstable phonon (the “soft mode”) whose frequency changes as the temperature is approaching a critical value TC (the phonon “softens”) becoming zero at TC. This implies that the correspondent vibration (or the atomic positions) become “frozen” at this temperature and produces a structure of another symmetry with a finite dipole moment. Thus, generating emergent topological relics.