Séminaire MatQ - Séminaire de maîtrise de Ashvini Vallipuram

Titre : Séminairede maîtrise -Investigating the phonon thermal Hall effect in insulators

Résumé : Say we have an electricalconductor. We decide to apply an electrical current along the x-axis and amagnetic field along the z-axis. Since electrons are charged particles, theyfeel a Lorentz force and they get deviated from their initial trajectory. A potentialdifference can now be measured along the y-axis. This is what we call the electricalHall effect. Now, using the same setup, we send a heat current along the x-axisinstead of an electric current, and when we apply a magnetic field along thez-axis, we can now measure a temperature difference along the y-axis. Thismakes sense since electrons carry electricity but also heat! Now, when thematerials we apply this technique to are insulators, we don’t expect to observethis temperature difference, since electrons in insulators don’t move. Surprisingly,it turns out that we do, and we observe this in a lot of insulators! Hence, Iwill talk about some studies that I performed during my master’s to get moreinformation about this, namely the puzzling phenomenon of the phonon thermalHall effect.