Cormac Mc Guinness Cormac Mc Guinnesstcd ie Physics
- Slides: 12
Cormac Mc. Guinness Cormac. Mc. Guinness@tcd. ie Physics Department Trinity College Dublin X-ray Emission Spectroscopy • 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-Zn. O and Co-Sn. O 2 Experimental & Theoretical Measurements: (approximately 4 -5 weeks beamtime per year) – SXE / XAS at: • O K (1 s) edge –> O 2 p states • Co L 2, 3 (2 p) edge -> Co 3 d, 4 s states – RIXS measurements at: • O K (1 s) edge –> O 2 p -> Co 3 d excitations • Co L 2, 3 (2 p) edge -> Co 3 d->3 d excitations & Co 3 d-> O 2 p excitations – SXE/XMCD measurements • Measure element specific spin and orbital moments • Theoretical: – Modelling of metal 2 p RIXS spectra using appropriate multiplet structure codes • Instrumentation: – Development of instrumentation for SXEXMCD measurements
Core Level Spectroscopy Unoccupied states Fermi level Occupied states Core level Laser spectroscopy Excitations of valence electrons
Photoelectron Spectroscopy
X-ray Absorption Spectroscopy Dipole selection rule Cr. O 2:
X-ray Emission Spectroscopy Dipole selection rule Cr. O 2:
Resonant Inelastic X-ray Scattering Radiant resonant processes Ca. Cu 3 Ti 4 O 12: Ti 2 p spectra
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-Zn. O and Co-Sn. O 2 Experimental & Theoretical Measurements: (approximately 4 -5 weeks beamtime per year) – SXE / XAS at: • O K (1 s) edge –> O 2 p states • Co L 2, 3 (2 p) edge -> Co 3 d, 4 s states – RIXS measurements at: • O K (1 s) edge –> O 2 p -> Co 3 d excitations • Co L 2, 3 (2 p) edge -> Co 3 d->3 d excitations & Co 3 d-> O 2 p excitations – SXE/XMCD measurements • Measure element specific spin and orbital moments • Theoretical: – Modelling of metal 2 p RIXS spectra using appropriate multiplet structure codes • Instrumentation: – Development of instrumentation for SXEXMCD measurements
Cormac Mc. Guinness Cormac. Mc. Guinness@tcd. ie Physics Department Trinity College Dublin X-ray Emission Spectroscopy • Soft x-ray emission and resonant inelastic x-ray scattering of transition metal doped semiconductors
Copper Phthalocyanine • Localized probe • Photon in/Photon out spectroscopy • Photon energies ~ 300 -900 e. V 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
