The mission of the Phonon Optimized Engineered Materials (POEM) Center is experimental and theoretical investigation of phonon properties of advanced materials and development of innovating methods for controlling phonon transport with applications in electronics, optoelectronics and direct energy conversion.

Brillouin-Mandelstam Light Scattering

Brillouin-Mandelstam light scattering (BMS) is the inelastic scattering of the light by thermally excited phonons (or magnons) which offers non-contact and high spatial resolution measurements. The BMS instrument can be used for studying acoustic phonons and magnon close to the Brillouin zone center. Both light scattering from the bulk, i.e. the volume of the sample, via the elasto-optic mechanism and from the surface of the sample, via the surface ripple mechanism can be detected with the BMS instrument.

Low-Frequency Noise Spectroscopy

Raman spectroscopy is an inelastic light scattering technique, which provides information about elemental excitations, e.g. phonons and magnons, in solids and molecules. Raman spectroscopy became crucially important for determining materials’ and nanostructures’ composition, crystal structure, quality, mechanical stress and other characteristics. Professor Balandin and co-workers developed a Raman spectroscopy based method for measuring thermal conductivity of graphene and other 2D materials and thin films. A specially designed Raman Spectroscopy Laboratory – part of Professor Balandin’s Phonon Optimized Engineered Materials (POEM) Center features a unique micro-Raman spectrometer with the low wavenumber capability, several excitation lasers, including UV, and low and high temperature ranges for measurements. A combination of Raman and Brillouin-Mandelstam spectroscopy at POEM Center allows one to investigate phonons and magnons in the entire frequency range from acoustics to optics.

Thermal Characterization of Materials

The thermal characterization equipment available at the Phonon Optimized Engineered Materials (POEM) Center include several thermal conductivity measurement setups such as Netzsch “Nano Flash” LFA thermal diffusivity and conductivity measurement system operating in the temperature range from 80 K to 800 K; transient planar source “Hot-Disk” TPS system with the automatic hot-cold bath for temperature control; transient “Hot-Wire” TT-TC system; MMR Tech Seebeck-effect measurement system; Analysis Tech Thermal Interface Material Tester, which measures thermal conductivity in the thermal interface materials used in electronic packaging; separate tools for measuring specific heat of the materials. The POEM Center also features the original Raman optothermal technique developed by Professor Balandin and co-workers for measurements of the thermal conductivity of graphene and other 2D materials.