Speaker
Description
In a metal the Fermi Surface is the separation – in momentum space – between occupied and unoccupied states. Here, thermal excitation are possible and rearrangements of the electronic structures such as the superconducting instability, magnetic moment formation and charge density wave-like phase transitions can be driven by the electronic states on the Fermi surface.
Angle-resolved photoelectron spectroscopy (ARPES) can map the Fermi surface of a crystalline solid thanks to conservation of momentum in the photoemission process. The method is highly surface sensitive thus inevitably the momentum component perpendicular to the surface (k_perp) is less well resolved than the fully conserved parallel momentum (k_par).
In this presentation we will demonstrate the importance of tuning the total momentum (k) and thus k_perp to precisely determine relevant questions of solid state spectroscopy, such as the precise arrangement of bands in the multi-sheet Fermi surface of FeSe, quasi-one-dimensional Tl2Mo6Se6, and the distinction between bulk-pockets and surface states in epitaxial films of Gd-doped EuO. As an outlook we will discuss the prospect of performing precise spectral function measurements, a strength of ARPES, across a wide range of photon energies.
