Exploring the X-ray coherence to investigate the role played by charge density wave ordering on unconventional superconductors

• Grant number: 22/16322-6
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): March 01, 2023
• Effective date (End): August 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Ricardo Donizeth dos Reis
• Grantee: André Antonio Martins Chagas e Silva
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovações (Brasil). Campinas , SP, Brazil
• Associated research grant: 18/00823-0 - New topological states of matter under extreme conditions, AP.JP

Abstract

This PhD project aims to advance the understanding of the relationship between a periodic pattern of conduction electrons called charge density wave (CDW), and another quantum order, superconductivity, or zero electrical resistance, in the same material. Here we propose to take advantage of the opportunities opened by the 4th generation Synchrotron which allow the realization of experiments using X-ray coherences, such as coherent diffraction imaging (CDI) and ptychography, shedding light on the open question of whether CDW phase is relevant for a superconductivity. Moreover, we will combine the X-ray experiments with external pressure (hydrostatic and uniaxial), low temperature and high magnetic field to have a continuous, clean and reversible tuning of both CDW and superconductivity ordering. In particular, we will focus our investigations on the family of materials, called quasi two-dimensional Kagome metals AV3Sb5 (A = K, Rb Cs), in which besides the coexistence between CDW and superconductivity exhibits topological properties. Our aim is to use external pressure, both hydrostatic and uniaxial, low temperature and high magnetic fields to push materials through the critical region where the state of matter changes and the inherently quantum effects dominate. Electronic, magnetic and structural properties will be measured as function of the lattice contraction and the resulting data compared with predictions of theoretical models. We hope that the results will provide advances in the central issue in condensed matter physics about understanding the competition between superconductivity, CDW and topological properties. (AU)