High-accuracy bulk electronic bandmapping with eliminated diffraction effects using hard X-ray photoelectron momentum microscopy

Babenkov, S.; Medjanik, K.; Vasilyev, Dmitry; Чернов, С. В.; Schlueter, Christoph; Gloskovskii, A.; Matveyev, Yu.; Drube, W.; Schönhense, B.; Elmers, H. J.; Schönhense, G.

doi:10.1038/s42005-019-0208-7

Cited by 31 publications

(42 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This suggests possible applications of hXPD for element-resolved strain analysis in materials [50,51]. Valence-band patterns are recorded at identical setting of the microscope [47] thus opening the path to a one-to-one correspondence of changes in the geometric and electronic structures, measured quasi simultaneously. Static and dynamic strain manipulation is emerging as a new avenue to tune and shape a material's electronic properties.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

High-resolution hard-x-ray photoelectron diffraction in a momentum microscope—the model case of graphite

et al. 2019

View full text Add to dashboard Cite

Hard x-ray photoelectron diffraction (hXPD) patterns recorded with a momentum microscope with high k-resolution (0.025 Å −1 equivalent to an angular resolution of 0.034°at 7 keV) reveal unprecedented rich fine structure. We have studied hXPD of the C 1s core level in the prototypical low-Z material Graphite at 20 photon energies between 2.8 and 7.3 keV. Sharp bright and dark lines shift with energy; regions of Kikuchi band crossings near zone axis exhibit a filigree structure which varies rapidly with energy. Calculations based on the Bloch wave approach to electron diffraction from lattice planes show excellent agreement with the experimental results throughout the entire energy range. The main Kikuchi bands in the [001] zone axis appear fixed on the momentum scale with a width of the corresponding reciprocal lattice vector, allowing to reconstruct the size of the projected Brillouin zone. The newly developed high-energy k-microscope allows full-field imaging of (k x , k y )-distributions in large k-fields (up to >22 Å −1 dia.) and time-of-flight energy recording.XPD cluster picture and dynamical electron scattering from lattice planes showed that the latter is more appropriate for very high energies. Hence, for the present study of hard x-ray photoelectron diffraction (hXPD) the dynamical scattering approach for bulk crystals is expected to be the more efficient theoretical description. By exploiting exchange scattering and multiplet splittings, even antiferromagnetic short-range order has been probed by XPD [17,18].Experimentally, XPD is studied using angular-resolved photoelectron spectroscopy. Large polar angular ranges of typically 0°-60°can be observed, mostly by rotating the sample about its surface normal (e.g. [8,10,11]). But also display-type electron analysers were developed [19][20][21] which give direct 2D full-field angular distributions in a wide angular range [22][23][24][25]. One main emphasis was to observe the pronounced forward scattering along atom rows in off-normal directions [4,8], hence the trend to observe a maximum polar angular range. Typical angular resolutions in both angular-scanning and display-type recording modes are ∼1°, but in some cases higher resolutions (<1°FWHM) have been reached [26][27][28].Here we present the first study of XPD using the new technique of momentum microscopy. In this type of photoelectron analyser, a cathode-lens (usually with an electrostatic extractor field) yields a reciprocal image in its backfocal plane (BFP), which is magnified on the image detector. This recording mode bears several essential differences in comparison with previous approaches: The diffractograms are observed in reciprocal space (i.e. on a momentum scale) instead of real-space polar coordinates. The k-field of view in the present study is up to ∼14 Å −1 at 7 keV, corresponding to a small polar angular range of 0°-9°. The k-resolution of ∼0.03 Å −1 corresponds to an angular resolution of 0.03°. For the small angular range, full-field imaging works without sample rotation, similar to...

show abstract

Section: Discussionmentioning

confidence: 99%

“…Measurements for tungsten yielded m eff /m e =1.07 at 1 keV [38] and 1 at 6 keV [46]. For Mo we found m eff /m e =1.03 at 460 eV and m eff /m e =1 already at 1.7 keV [47]. For these reasons, the panels list the final-state energies and not the photon energies.…”

Section: Carbon 1s Diffractogramsmentioning

confidence: 94%

High-resolution hard-x-ray photoelectron diffraction in a momentum microscope—the model case of graphite

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Therefore, despite the low photoexcitation cross sections at high photon energies also momentum microscopy in the HAX-PES regime should be feasible. This was demonstrated very recently using a time-of-flight spectrometer [41].…”

Section: Haxpes Spectromicroscopymentioning

confidence: 91%

From Photoemission Microscopy to an “All-in-One” Photoemission Experiment

Tusche

Chen

Pluciński

et al. 2020

e-J. Surf. Sci. Nanotechnol.

View full text Add to dashboard Cite

Photoelectron spectroscopy is our main tool to explore the electronic structure of novel material systems, the properties of which are often determined by an intricate interplay of competing interactions. Elucidating the role of this interactions requires studies over an extensive range of energy, momentum, length, and time scales. We show that immersion lens-based momentum microscopy with spin-resolution is able to combine these seemingly divergent requirements in a unifying experimental approach. We will discuss applications to different areas in information research, for example, resistive switching and spintronics. The analysis of resistive switching phenomena in oxides requires high lateral resolution and chemical selectivity, as the processes involve local redox processes and oxygen vacancy migration. In spintronics topological phenomena are currently a hot topic, which lead to complex band structures and spin textures in reciprocal space. Spin-resolved momentum microscopy is uniquely suited to address these aspects.

show abstract

“…In order to overcome the intensity/resolution problem of photoelectron spectroscopy in the X‐ray range, we have developed a conceptually new approach, termed time‐of‐flight (ToF) momentum microscopy. Based on work at low energies we extended the method at first to the soft X‐ray range and in summer 2018 to the hard X‐ray range employing a special high‐energy optics . In contrast to conventional electron analyzers that are working in terms of angular coordinates, these photoelectron microscopes directly measure the (lateral) k x ‐ and k y ‐coordinates in a large range of up to 20 Å −1 diameter.…”

Section: The Methodsmentioning

confidence: 99%

“…Panel (f) shows the corresponding spectrum, the narrow peak labeled hν originates from scattered photons and gives a marker for time‐zero. Previous work has shown that there is a significant XPD contribution in the valence‐band patterns. In order to eliminate this effect, the raw data have been corrected using a C 1s diffraction pattern taken at the same kinetic energy as the valence pattern.…”

Section: Photoelectron Momentum Microscopymentioning

confidence: 99%

Electron‐ and X‐Ray Spectroscopies of Organic Charge‐Transfer Complexes

Medjanik

Elmers

Schönhense

et al. 2019

Physica Status Solidi (b)

View full text Add to dashboard Cite

Recent work aiming at a deeper understanding of the electronic properties of classical and novel charge‐transfer (CT) complexes is reviewed herein. From a variety of studied CT salts, the prototypical examples TTF‐TCNQ, (TMTTF)2SbF6, (TMTSF)2PF6, and TMP/HMP‐TCNQ have been selected. Three different types of electron and X‐ray spectroscopies were applied, namely ultraviolet photoelectron spectroscopy (UPS), hard X‐ray photoelectron spectroscopy (HAXPES), and near‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy. Using UPS, the development of the valence band structure during co‐deposition of the donor and acceptor moieties TMP/HMP and TCNQ has been studied. The spectra reveal characteristic level shifts and a strong reduction of the HOMO–LUMO gap upon formation of the complex. HAXPES probes the core levels and reveals characteristic shifts of the binding energies in (TMTTF)2SbF6 at the phase transition to the low‐temperature charge‐ordered state. NEXAFS is a local, element‐specific probe for the unoccupied bands above the Fermi level and reveals changes in the population of specific orbitals when the CT complex is formed. As an outlook, the novel method of photoelectron momentum microscopy is presented, giving access to the valence bands and core‐levels and in particular to high‐resolution X‐ray photoelectron diffraction patterns.

show abstract

High-accuracy bulk electronic bandmapping with eliminated diffraction effects using hard X-ray photoelectron momentum microscopy

Cited by 31 publications

References 40 publications

High-resolution hard-x-ray photoelectron diffraction in a momentum microscope—the model case of graphite

High-resolution hard-x-ray photoelectron diffraction in a momentum microscope—the model case of graphite

From Photoemission Microscopy to an “All-in-One” Photoemission Experiment

Electron‐ and X‐Ray Spectroscopies of Organic Charge‐Transfer Complexes

Contact Info

Product

Resources

About