Electronic structure and magnetic excitations of magnetic superconductors

• Grant number: 19/05150-7
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): June 01, 2019
• Effective date (End): November 30, 2022
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal researcher: Fernando Assis Garcia
• Grantee: Marli dos Reis Cantarino
• Home Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 20/13701-0 - ARPES study of the electronic structure in iron-based superconductors, BE.EP.DR

Abstract

Iron Based Superconductors (IBS) are an interesting family of magnetic materials in which high temperature superconductivity appears. The understanding of the superconductor transition so far, relates this phase with magnetic fluctuations in the material: under the effect of electron or whole doping, the magnetic order is suppressed and the superconductivity emerges. To characterize the magnetic fluctuations we resort to Resonant Inelastic X-ray Scattering (RIXS), a element specific synchrotron based technique, which detects the momentum and energy absorbed by the material related to different types of elementary excitations in a solid. Due to the itinerant behavior of spins in this family of materials, other relevant technique is Angle Resolved PhotoEmission Spectroscopy (ARPES), by means of which the electronic structure of a material can be determined. These two techniques are complementary to one another in the sense that knowledge of the electronic structure (obtained by ARPES) gives support to the interpretation of the magnetic excitation spectra (obtained by RIXS). Thus, this project consists of investigating the relation between magnetic excitations and the onset of superconductivity in a family of high temperature superconductors. The candidate will learn and acquire experience with both techniques, performing RIXS and ARPES experiments of selected Ba(Fe1-xTM)2As2 (TM = transition metals) IBS. This project will be co-supervised by Tulio Costa Rizuti da Rocha (CNPEM-SIRIUS) that is responsible of the state of the art facilities of the new Ipê beamline. Dr. da Rocha will supervise the candidate during instrumentation work in in the Ipê beamline. Moreover, with the support of the BEPE program, we propose an exchange period in the group of Dr. Claude Felix Monney at the University of Friburg. Under the supervision of Dr. Monney, the candidate will apply time resolved ARPES to IBS and other materials of interest. (AU)