Lattice and spin dynamics is crucial for understanding many material properties such as thermal transportation, thermal expansion, and phase transformation with many important science and engineering applications in energy materials, photonics materials, structural materials, and nano-devices.
Spin waves and phonons are strongly coupled in many ferromagnetic and antiferromagnetic structures.
Application: controlling heat flow on nanoscale, manipulating spin coherence
Supported by: Thermal Transport Process Program, CBET, NSF
Phonons in low dimension
Lattice dynamics is significantly affected by the dimension of materials though phonon confinement and structure modification. We investigate the phonons in 2-D (thin films, thin superlattices), 1-D (nanothreads), and 0-D (quantum points, nanoparticles).
Application: photonics materials, structure materials
Thermal transport under high pressure
We study the transport in materials under these extreme environments for energy applications and phonon engineering.
Application: thermoelectrics, phonon engineering, photonics materials, vdW materials
Interfacial thermal transport
We study the effects of phonon anharmonicity on the interfacial thermal conductance.
Application: power electronics
Lattice thermal transport can be suppressed by phonon nesting, resonance, nanostructure, doping, and many other approaches.
Application: thermoelectrics, thermal management
Negative thermal expansion
Exotic phonons may induce negative thermal expansion in structural materials through anharmonicity.
Application: controlling the thermal expansion of structural materials
Phonon anhamonicity and lifetime
Anharmonicity of bulk or low-dimension materials (metals, alloys, oxides, …) due to phonon-phonon interactions can be probe by their phonon Grüneisen parameters and lifetime.
Application: correlate anharmonicity and their thermodynamical effects
Frustrated magnetic ordering in antiferromagnetic materials allow abnormal spin fluctuations and competing ordering.