Juan Antonio Seijas started his PhD at the ICMAB, and his thesis, within the Theory and Simulation Group, has been focused on the phonon properties of the materials. He has also been active in organizing the PhD Meeting of 2017. Now, he would like to become a secondary high school teacher. We wish you all the luck!

Juan Antonio Seijas giving his speech after defending the thesis!

Computational studies of thermal transport in functional oxides

by Juan Antonio Seijas Bellido, Theory and Simulation Group at ICMAB-CSIC

Date: Thursday, 3 October 2019
Time: 11 am
Venue: ICMAB - Sala d'Actes Carles Miravitlles

Abstract: 
In this thesis we have presented two different methods to distort the crystal lattice of different oxides, which are applying an external electric field and strain. We do that to modify the phonon bands of the material and modulate their thermal conductivity. This allow us to overcome the difficulty of modifying the behaviour of phonons due to their lack of mass and net charge. We have performed theoretical studies using two different simulations techniques: solving the Boltzmann Transport Equation and performing Molecular Dynamics simulations.

Many interesting results have been obtained for the first time, like que quantification of the thermal boundary resistance of a domain wall in the PTO or the effect of the uniaxial strain in the thermal properties of the ZnO. All of this have been achieved going into the detail in the phonon properties of the materials, providing explanation for the facts at a very fundamental level.

Supervisors:

• Riccardo Rurali, ICMAB-CSIC
• Jorge Íñiguez, Luxembourg Institute of Science and Technology (LIST)

PhD Committee:

• President: Miguel Rubí, UB, Spain
• Secretary: Alejandro Goñi, ICMAB-CSIC, Spain
• Vocal:  Marty Gregg, Queen’s University Belfast, United Kingdom