Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 22: 2D Materials II: Electronic Structure (joint session O/TT)

O 22.3: Vortrag

Dienstag, 19. März 2024, 11:15–11:30, MA 005

Orbital angular momentum of Cr₂Ge₂Te₆ bands using circular dichroism — •Honey Boban¹, Mohammed Qahosh¹, Xiao Hou¹, Tom G Saunderson^2,3, Yuriy Mokrousov^2,3, Claus Michael Schneider¹, and Lukasz Plucinski¹ — ¹Peter Gruenburg Institute-6, Forschungszentrum Juelich, Germany — ²Peter Gruenburg Institute-1, Forschungszentrum Juelich, Germany — ³University of Mainz, Germany

We present high-resolution circular-dichroic angle-resolved photoemission (CD-ARPES) spectra from graphene, WSe₂, and Cr₂Ge₂Te₆ (CGT), materials that exhibit different levels of band structure complexity. In graphene, where bands near the Fermi level are of single C 2p_z orbital nature, we investigated various contributions to dichroism, such as phase shifts and final state scattering, by varying the photon energy. In WSe₂, near the valence band maximum Γ and K points we found strong contribution of dichroism derived from the experimental geometry, in the light incidence angle dependent CD-ARPES. We use these findings to study the OAM texture of a 2D ferromagnetic material CGT [1], in which the time reversal symmetry is broken and mirror planes are absent. CGT is interesting as it offers a platform to study the interplay of ferromagnetism and spin orbit coupling, and is a potential candidate for future spintronic devices where both spin degree of freedom and orbital degree of freedom can be utilized. Therefore, understanding the initial band OAM in CGT is crucial, as it is closely linked to its quantum transport properties [2]. Ref: [1] J. Phys. Condens. Matter 7, 69(1995), [2] Rev. Mod. Phys. 82, 1539(2010)

Keywords: Angle resolved photoemission spectroscopy; Circular dichroism; Orbital angular momentum; 2D materials; Band structure