The magnetism of terahertz phonons

• Grant number: 25/02029-3
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: July 01, 2025
• End date: April 30, 2029
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Felix Guillermo Gonzalez Hernandez
• Grantee: Eduardo Destefani Stefanato
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 21/12470-8 - Research in quantum materiais involving intense magnetic fields and low temperatures, AP.TEM

Abstract

Phonons, collective excitations of a crystalline lattice, determine many of the physical properties of solids, including electrical, thermal, and optical characteristics. By exciting or controlling specific phonon modes, one can modify material properties, such as critical phase transition temperatures, or even induce quantum effects such as superconductivity. In particular, chiral phonon modes, demonstrated in various materials over the past six years, carry angular momentum and thus couple directly to magnetic fields. Notably, their magnetic moments are predicted to be strongly influenced by electronic contributions. In this project, we plan to study the magnetic moment of chiral phonons using terahertz time-domain spectroscopy in quantum materials-materials that exhibit strong correlations and interactions between various degrees of freedom (charge, spin, orbital, and lattice dynamics), leading to exotic phenomena and novel phase transitions. Specifically, we will investigate the polarization and coupling of these optical phonons with terahertz photons in nanostructured thin films. (AU)