Spin- and time-resolved photoelectron spectroscopy and diffraction studies using time-of-flight momentum microscopes
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2021
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866909226371121152 |
|---|---|
| author | Schönhense, Gerd Elmers, Hans-Joachim |
| author_facet | Schönhense, Gerd Elmers, Hans-Joachim |
| contents | Momentum microscopy (MM) is a novel way of performing angular-resolved photoelectron spectroscopy (ARPES). Combined with time-of-flight (ToF) energy recording, its high degree of parallelization is advantageous for photon-hungry experiments like ARPES at X-ray energies and spin-resolved ARPES. This article introduces into the spin-resolved variant of ToF-MM and illustrates its performance by selected examples obtained in different spectral ranges. In a multidimensional view of the photoemission process, spectral density function $ρ(k,E_B)$, spin polarization $P(k,E_B)$ and related quantities of circular dichroism in the angular distribution (CDAD) are part of the complete experiment, a concept adopted from atomic photoemission. We show examples of spin-resolved valence-band mapping in the UV, VUV, soft- and hard-X-ray range. Spin mapping of the Heusler compounds Co$_2$MnGa and Co$_2$Fe$_{0.4}$Mn$_{0.6}$Si at $hν=6$~eV prove that the second compound is a half-metallic ferromagnet. Analysis of the Tamm state on Re(0001) using VUV-excitation reveals a Rashba-type spin texture. Bulk band structure including Fermi surface, Fermi velocity distribution $v_F(k,E_F)$, full CDAD texture and spin signature of W(110) have been derived via tomographic mapping with soft X-rays. Hard X-rays enable accessing large k$_{par}$-regions so that the final-state sphere crosses many Brillouin zones in $k$-space with different $k_z$. At $hν=5.3$~keV this fast 4D mapping mode (at fixed $hν$) revealed the temperature dependence of the Fermi surface of the Kondo system YbRh$_2$Si$_2$. Probing the true bulk spin polarization of Fe$_3$O$_4$ at $hν=5$~keV proved its half-metallic nature. The emerging method of ToF-MM with fs X-ray pulses from a free-electron laser enables simultaneous valence, core-level and photoelectron diffraction measurements in the ultrafast regime. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2110_13832 |
| institution | arXiv |
| publishDate | 2021 |
| record_format | arxiv |
| spellingShingle | Spin- and time-resolved photoelectron spectroscopy and diffraction studies using time-of-flight momentum microscopes Schönhense, Gerd Elmers, Hans-Joachim Materials Science Momentum microscopy (MM) is a novel way of performing angular-resolved photoelectron spectroscopy (ARPES). Combined with time-of-flight (ToF) energy recording, its high degree of parallelization is advantageous for photon-hungry experiments like ARPES at X-ray energies and spin-resolved ARPES. This article introduces into the spin-resolved variant of ToF-MM and illustrates its performance by selected examples obtained in different spectral ranges. In a multidimensional view of the photoemission process, spectral density function $ρ(k,E_B)$, spin polarization $P(k,E_B)$ and related quantities of circular dichroism in the angular distribution (CDAD) are part of the complete experiment, a concept adopted from atomic photoemission. We show examples of spin-resolved valence-band mapping in the UV, VUV, soft- and hard-X-ray range. Spin mapping of the Heusler compounds Co$_2$MnGa and Co$_2$Fe$_{0.4}$Mn$_{0.6}$Si at $hν=6$~eV prove that the second compound is a half-metallic ferromagnet. Analysis of the Tamm state on Re(0001) using VUV-excitation reveals a Rashba-type spin texture. Bulk band structure including Fermi surface, Fermi velocity distribution $v_F(k,E_F)$, full CDAD texture and spin signature of W(110) have been derived via tomographic mapping with soft X-rays. Hard X-rays enable accessing large k$_{par}$-regions so that the final-state sphere crosses many Brillouin zones in $k$-space with different $k_z$. At $hν=5.3$~keV this fast 4D mapping mode (at fixed $hν$) revealed the temperature dependence of the Fermi surface of the Kondo system YbRh$_2$Si$_2$. Probing the true bulk spin polarization of Fe$_3$O$_4$ at $hν=5$~keV proved its half-metallic nature. The emerging method of ToF-MM with fs X-ray pulses from a free-electron laser enables simultaneous valence, core-level and photoelectron diffraction measurements in the ultrafast regime. |
| title | Spin- and time-resolved photoelectron spectroscopy and diffraction studies using time-of-flight momentum microscopes |
| topic | Materials Science |
| url | https://arxiv.org/abs/2110.13832 |