Numerical Approaches to Theory of Spectroscopy in Correlated Materials

Download or read book Numerical Approaches to Theory of Spectroscopy in Correlated Materials written by Cheng-Chien Chen and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Strongly correlated systems exhibit novel phenomena such as superconductivity and magnetism that arise from the interplay between many intertwined degrees of freedom. In this dissertation I discuss my work using state-of-the-art exact diagonalization simulations in attempts to understand the physics of correlated materials via their response to various experimental probes. I first discuss simulating x-ray absorption spectra to extract crucial information regarding correlation effects in iron-based superconductors and the pressure-induced phase transitions in hematite. I then discuss modeling resonant inelastic x-ray scattering spectra of the cuprate superconductors and studying the orbital characters of the excitation profiles. Following the discussion of photon-based spectroscopies, I then shift the focus to magnetic properties of iron-based superconductors. I will discuss a possible orbital ordering scenario in connection with the orthorhombic anisotropies observed in neutron scattering, transport, and other spectroscopic experiments performed on these materials. At the end of the dissertation, I examine the role of magnetic frustration and demonstrate how the response of antiferromagnets to non-magnetic impurities and magnetic Raman scattering can reveal the degree of frustration and help narrow the possible models for the iron-pnictide materials.