X-ray Absorption Spectroscopy of Fe-based Superconductors

• Grant number: 25/06845-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2025
• End date: May 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Fernando Assis Garcia
• Grantee: Esther Leite dos Santos
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 24/13291-8 - Disentangling Electronic excitations in Hund Metals, AP.R

Abstract

The term "Fe-based superconductors" (FeSCs) denotes a large family of electronically correlated materials associated with a rich phenomenology of diverse electronic phases. These include unconventional and high temperature superconductors, but also magnetic phases and the so-called electronic nematic phase. Essential to understanding this rich phenomenology is the study of the electronic structure of FeSCs. In this work, the topic is approached from the perspective of local electronic states. We propose to characterize the 3d electronic states, derived from Fe, the4p states, derived from As, and the hybrid Fe3dAs4p states. The chosen tool is X-ray absorption spectroscopy (XAS) at the Fe and As K-edges, in polarization-dependent experiments. Our goal is to introduce the student to the study of Hund metals through a gentle path while at the same time leaving open the possibility of an original contribution to this field of study.