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Peter Puschnig, APS March Meeting, Boston 2012
Motivation
Orbital tomography:Deconvoluting photoemission spectra of organic molecules
Austria Austria Germany Austrian Science FundP23190-N16
ARPES of PTCDA / Ag(110)ARPES of PTCDA / Ag(110)
Peter Puschnig, APS March Meeting, Boston 2012
Glöckler et al,Surf. Sci. 405, 1-20 (1998).STM
Slide 1
Identifying OrbitalsIdentifying Orbitals
Slide 2Peter Puschnig, APS March Meeting, Boston 2012
Identifying OrbitalsIdentifying Orbitals
Self-interactioncorrected functional
Peter Puschnig, APS March Meeting, Boston 2012 Slide 3
ARPES of PTCDA / Ag(110)ARPES of PTCDA / Ag(110)
Peter Puschnig, APS March Meeting, Boston 2012
Glöckler et al,Surf. Sci. 405, 1-20 (1998).STM
Slide 1
Photoemission IntensityPhotoemission Intensity
One Step Model
Peter Puschnig, APS March Meeting, Boston 2012 Slide 4
Photoemission IntensityPhotoemission Intensity
molecular orbital
One Step Model
Peter Puschnig, APS March Meeting, Boston 2012 Slide 4
Photoemission IntensityPhotoemission Intensity
[Feibelman and Eastman, Phys. Rev. B 10, 4932 (1974).]
Approximation: final state = plane wave
Fourier Transform of Initial State Orbital
plane wave ei k r
One Step Model
molecular orbital
Peter Puschnig, APS March Meeting, Boston 2012 Slide 4
Comparison with DFTComparison with DFT
Molecular Orbitalin Real Space
Calculation ofthe Fourier Transform kx (1/Å)
Hemispherical Cut Through3D Fourier Transform
x
kx (1/Å)
k y (
1/Å
)
kz (1/Å
)
y
z
Peter Puschnig, APS March Meeting, Boston 2012
ky (1/Å
)
Slide 5
Peter Puschnig, APS March Meeting, Boston 2012 Slide 6
The Toroidal Electron Spectrometer for Angle-Resolved Photoelectron Spectroscopy with Synchrotron Radiation at BESSY II
Toroidal Electron Energy AnalyzerToroidal Electron Energy Analyzer
HOMO and Filled LUMOHOMO and Filled LUMO
Puschnig et al. PRB 84, 235427 (2011), Ziroff et al., PRL 104, 233004 (2010).
Peter Puschnig, APS March Meeting, Boston 2012
M1=FLUMO
M2=HOMO
Slide 6
What is the nature of M3?What is the nature of M3?
M2=HOMO
M1=FLUMO
?
Peter Puschnig, APS March Meeting, Boston 2012 Slide 7
ARPES Data-CubeARPES Data-Cube
Peter Puschnig, APS March Meeting, Boston 2012 Slide 8
Eb
kx
ky
ππ -„bands“ of PTCDA-„bands“ of PTCDA
Peter Puschnig, APS March Meeting, Boston 2012 Slide 9
What is the Origin of M3?What is the Origin of M3?
Peter Puschnig, APS March Meeting, Boston 2012
E C F
Slide 10
What is the Origin of M3?What is the Origin of M3?
Peter Puschnig, APS March Meeting, Boston 2012
E C F
Puschnig et al. PRB 84, 235427 (2011), see also: Dauth et al., PRL 107, 193002 (2011).
Slide 11
Projected DOS from ARPES!Projected DOS from ARPES!
Peter Puschnig, APS March Meeting, Boston 2012
C
D
E
F
-3.8 -3.6 -3.4 -3.2 -3.0 -2.8
Eb (eV)
measuredphotemission
data cube
calculatedorbitals
Fit parameters= PDOS
Slide 12
Benchmark for TheoryBenchmark for Theory
Peter Puschnig, APS March Meeting, Boston 2012
C
D
E
F
Slide 13
[1-1
0]
Ag-
row
dire
ctio
n
ConclusionConclusion
Peter Puschnig, APS March Meeting, Boston 2012 Slide 14
Orbital Tomography● Make use of characteristic momentum space patterns● Unambiguous identification of molecular features● Density of states projected onto molecular orbitals● Deconvolution beyond limits of energy resolution
Other ApplicationsReal space reconstruction of molecular orbital densities
Puschnig et al., Science 326, 702 (2009).
Hybridization of molecular orbitals mit metallic states
Ziroff et al., Phys. Rev. Lett. 104, 233004 (2010).
Berkebile et al., Phys. Chem. Chem. Phys. 13, 3604 (2011).