Phonon resonance % reductions 1 Collective modes 1 Crystal lattices 1 Electron-phonon interactions 1 Electronic excitation 1 Gallium nitride 1 III-V semiconductors 1 Magnetic fields 1 Magnetic-field 1 Metals 1 NanoPillar 1 Nanophononic metamaterial 1 Nanophononics 1 Phonons 1 Polar metals 1 Property 1 Soft-phonon mode 1 Spin flip 1 Spin orbits 1 Spin-orbit couplings 1 Thermal conductivity 1 Thermal transport 1 Thermo-Electric materials 1 Thermoelectric 1 Thermoelectric energy conversion 1 Thermoelectric equipment 1 Thermoelectric material 1 Thermoelectricity 1 Wide band gap semiconductors 1