x-ray emission spectroscopy
DESCRIPTION
Cormac McGuinness [email protected] 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. - PowerPoint PPT PresentationTRANSCRIPT
X-ray Emission Spectroscopy
Cormac [email protected]
Physics DepartmentTrinity College Dublin
•Soft x-ray emission and resonant inelastic x-ray scattering of transition metal doped semiconductors
Project SummaryProject Summary
• Study of electronic structure of transition metal-doped wide bandgap semiconductor oxide systems – i.e. magnetic semiconductors such as Co-ZnO and Co-SnO2
• Experimental & Theoretical
• Measurements: (approximately 4-5 weeks beamtime per year)– SXE / XAS at:
• O K (1s) edge –> O 2p states
• Co L2,3 (2p) edge -> Co 3d, 4s states
– RIXS measurements at:• O K (1s) edge –> O 2p -> Co 3d excitations
• Co L2,3 (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 ofvalence electrons
kinB EhE
Photoelectron Spectroscopy
X-ray Absorption Spectroscopy
1lDipole selection rule
ps 21
CrO2:
524 526 528 530 532 534 536 538 540 542 544 546
CrO2 O K SXA
Inte
nsity
Energy (eV)
E || a E || c
X-ray Emission Spectroscopy
1lDipole selection rule
sp 12
CrO2:
-12 -10 -8 -6 -4 -2 0 2 4 6
O 2py-x
O 2py+x
+ O 2pz
Energy with respect to EF (eV)
DO
S
515 520 525 530 535
Inte
nsity
Emission energy (eV)
SXE E || a SXE E || c
CaCu3Ti4O12: Ti 2p spectra
456 458 460 462 464 466 468
En erg y (eV)
-20 -15 -10 -5 0
-20 -15 -10 -5 0
DCB
A
Energy Loss (eV)
435 440 445 450 455 460 465 470 475 480
435 440 445 450 455 460 465 470 475 480
Energ y (eV)
Ti LTi L
Cu L
Cu L
Resonant Inelastic X-ray Scattering
Radiant resonant processes
1.0
0.8
0.6
0.4
0.2In
tens
ity
(Arb
itra
ry U
nits
360
0 se
cond
s)
820800780760740720700680660640620
Emission Energy (eV)
Fe L3MValenceEmission
Fe L2MValenceEmission
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-SnO2
• Experimental & Theoretical
• Measurements: (approximately 4-5 weeks beamtime per year)– SXE / XAS at:
• O K (1s) edge –> O 2p states
• Co L2,3 (2p) edge -> Co 3d, 4s states
– RIXS measurements at:• O K (1s) edge –> O 2p -> Co 3d excitations
• Co L2,3 (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 [email protected]
Physics DepartmentTrinity 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 ~ 300-900 eV