Anomalous d-like surface resonances on Mo(110) analyzed by time-of-flight momentum microscopy

• Published in: Ultramicroscopy 2015-12, Vol.159, p.453-463
• Main Authors: Chernov, S.V., Medjanik, K., Tusche, C., Kutnyakhov, D., Nepijko, S.A., Oelsner, A., Braun, J., Minár, J., Borek, S., Ebert, H., Elmers, H.J., Kirschner, J., Schönhense, G.
• Format: Article
• Language: English
• Subjects: ARPES; Density; Dirac state; Dispersions; Electronics; Linear dichroism; Mathematical models; Microscopy; Momentum microscopy; Signatures; Surface layer; Surface resonance; Texture
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/j.ultramic.2015.07.008

The electronic surface states on Mo(110) have been investigated using time-of-flight momentum microscopy with synchrotron radiation (hν=35eV). This novel angle-resolved photoemission approach yields a simultaneous acquisition of the E-vs-k spectral function in the full surface Brillouin zone and several eV energy interval. (kx,ky,EB)-maps with 3.4Å−1 diameter reveal a rich structure of d-like surface resonances in the spin–orbit induced partial band gap. Calculations using the one-step model in its density matrix formulation predict an anomalous state with Dirac-like signature and Rashba spin texture crossing the bandgap at Γ¯ and EB=1.2eV. The experiment shows that the linear dispersion persists away from the Γ¯-point in an extended energy- and k∥-range. Analogously to a similar state previously found on W(110) the dispersion is linear along H¯−Γ¯−H¯ and almost zero along N¯−Γ¯−N¯. The similarity is surprising since the spin–orbit interaction is 5 times smaller in Mo. A second point with unusual topology is found midway between Γ¯ and N¯. Band symmetries are probed by linear dichroism. •First results taken with the novel time of flight momentum microscope for the Mo(110) surface taken with Synchrotron radiation are presented.•An anomalous band was found that bears much resemblance to a Dirac-type state.•A similar band was previously found only on the W(110) surface.