Tutorial SF03—Nanoscale Phonon and Nonequilibrium Transport—Raman Characterizations and First Principles Predictions

Instructors: Xinwei Wang, Iowa State University; Xiulin Ruan, Purdue University

Thermal transport at the atomic and nano-scales, including thermal conductivity and interface thermal conductance, is critical for scientific understanding and control of energy transport in many emerging applications. Moreover, energy carriers are often driven out of local thermal equilibrium in electronic and optoelectronic devices. This tutorial will cover both Raman characterizations and first principles-based calculations on these aspects.

Raman scattering-based techniques are one of most used for probing the above physical processes, partly because of its material-specific temperature probing capability. We will cover fundamentals of Raman spectroscopy, technical and physical challenges in Raman-based thermal characterization, and new techniques development. The learning objectives of this part include 1) systematic guidance for new scholars to establish and conduct Raman-based thermal characterization; 2) advanced physical analysis for time-domain design to realize high-level thermophysical characterization; and 3) suppressing or distinguishing conjugated transport processes toward ultimate level scientific understanding.

First principles calculations have emerged as a powerful tool to predict thermal, electrical, and optical properties without fitting parameters. The learning objectives of this theoretical part include:

1. First principles predictions of thermal conductivity, especially with the consideration of four-phonon scattering, phonon-electron scattering, and phonon renormalization
2. Multi-temperature model (MTM) coupled with first principles calculations to treat local thermal nonequilibrium among electrons and different phonon modes
3. First principles calculations of infrared optical/radiative properties

Tutorial Schedule