X-ray Emission Spectroscopy Cormac McGuinness Physics Department Trinity College Dublin Soft x-ray emission and resonant inelastic x-ray scattering of transition metal doped semiconductors

Project Summary Study of electronic structure of transition metal-doped wide bandgap semiconductor oxide systems – i.e. magnetic semiconductors such as Co-ZnO and Co-SnO 2 Experimental & Theoretical Measurements: (approximately 4-5 weeks beamtime per year) –SXE / XAS at: O K (1s) edge –> O 2p states Co L 2,3 (2p) edge -> Co 3d, 4s states –RIXS measurements at: O K (1s) edge –> O 2p -> Co 3d excitations Co L 2,3 (2p) edge -> Co 3d->3d excitations & Co 3d-> O 2p excitations –SXE/XMCD measurements Measure element specific spin and orbital moments Theoretical: –Modelling of metal 2p RIXS spectra using appropriate multiplet structure codes Instrumentation: –Development of instrumentation for SXEXMCD measurements

Core Level Spectroscopy Unoccupied states Occupied states Fermi level Core level Laser spectroscopy Excitations of valence electrons

Photoelectron Spectroscopy

X-ray Absorption Spectroscopy Dipole selection rule CrO 2 :

X-ray Emission Spectroscopy Dipole selection rule CrO 2 :

CaCu 3 Ti 4 O 12 : Ti 2p spectra Resonant Inelastic X-ray Scattering Radiant resonant processes

Soft X-ray spectrometer system

Project Summary Study of electronic structure of transition metal-doped wide bandgap semiconductor oxide systems – i.e. magnetic semiconductors such as Co-ZnO and Co-SnO 2 Experimental & Theoretical Measurements: (approximately 4-5 weeks beamtime per year) –SXE / XAS at: O K (1s) edge –> O 2p states Co L 2,3 (2p) edge -> Co 3d, 4s states –RIXS measurements at: O K (1s) edge –> O 2p -> Co 3d excitations Co L 2,3 (2p) edge -> Co 3d->3d excitations & Co 3d-> O 2p excitations –SXE/XMCD measurements Measure element specific spin and orbital moments Theoretical: –Modelling of metal 2p RIXS spectra using appropriate multiplet structure codes Instrumentation: –Development of instrumentation for SXEXMCD measurements

X-ray Emission Spectroscopy Cormac McGuinness Physics Department Trinity College Dublin Soft x-ray emission and resonant inelastic x-ray scattering of transition metal doped semiconductors

Copper Phthalocyanine Emission from the same excited atom (elemental probe) Dipole selection rules: l = ±1; s = 0; j = ±1, 0; mj = ±1, 0 (individual angular momentum resolved states) Direct comparison with angular momentum resolved DOS calculations Determine variations in the occupied states of similar materials Localized probe Photon in/Photon out spectroscopy Photon energies ~ eV