Thrust 2: Phonon and Magnon Engineering

Dr. Xiaoqin (Elaine) Li - University of Texas at Austin

Many fundamental excitations in matters such as phonons (coordinated lattice vibrations) and magnons (coordinated spin rotations also known as spin waves) can be probed using light scattering technique. A single frequency laser interacts (green peak in the picture) with the materials and goes through inelastic scattering, leading to scattered light with shifted frequencies (blue and red peaks in the pictures). In a particle picture, the incident photon interacts with a phonon or a magnon. This process satisfies energy and momentum conservation. If a phonon or magnon is absorbed (or emitted), the scattered photon has higher (or lower) energy, corresponding to the anti-Stokes (Stokes) peak in the spectrum. We investigate many fundamental questions related to phonons and magnons using Raman and Brillouin light scattering techniques such as phonon or magnon dispersion (i.e., how the energy changes as a function of the wavevector), how such dispersion is modified in confined structure, how phonons and magnons propagate in confined structures or under the spin transfer torque, and how the interaction between phonons and magnons influences thermal transfer in non-equilibrium systems.