Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter

Schönhense, G.; Medjanik, K.; Fedchenko, O.; Zymaková, A.; Chernov, S.; Kutnyakhov, D.; Vasilyev, D.; Babenkov, S.; Elmers, H.J.; Baumgärtel, P.; Goslawski, P.; Öhrwall, G.; Grunske, T.; Kauerhof, T.; von Volkmann, K.; Kallmayer, M.; Ellguth, M.; Oelsner, A.

doi:10.1107/S1600577521010511

Figure 7
Momentum patterns of bismuthene and zero-layer graphene on SiC(0001), recorded at the U125-2_NIM of BESSY II. Results have been recorded for bismuthene in a special `island-orbit' filling mode of the storage ring, in which four bunches travel on an orbit oscillating around the equatorial plane and for graphene in few-bunch mode. (a–d) k_x–k_y sections through a data array I(E_B,k_x,k_y), recorded at hν = 18 eV. The valence-band maximum lies 0.2 eV below E_F (a); the opening of the cones with increasing binding energy is visible in (b–d). (e) Structure of bismuthene on SiC(0001). (f–g) Analogous results for zero-layer graphene, recorded at hν = 23 eV with few-bunch filling of BESSY II. The Dirac point lies at E_F (f) and the opening cones show the well known triangular cross sections (g–j). For this sample a (2 × 2) superstructure is present, sketched as dashed triangles in the inset in (i). (k–p) E_B-versus-k_x sections showing the linear band dispersions for bismuthene (k–n) and graphene (o, p). Panels (m, n) show the cones of the first BZ and (p) shows the `mirrored cones' of the (2 × 2) structure.

JOURNAL OF
SYNCHROTRON
RADIATION

ISSN: 1600-5775

Volume 28| Part 6| November 2021| Pages 1891-1908

https://doi.org/10.1107/S1600577521010511

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