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O: Fachverband Oberflächenphysik

O 73: Electronic Structure of Surfaces 1

O 73.7: Vortrag

Donnerstag, 8. September 2022, 16:30–16:45, S053

Establishing fundamentals of ARPES spin textures with model material PtTe₂ — •Mohammed Qahosh, Honey Boban, Xiao Hou, Claus-Michael Schneider, and Lukasz Plucinski — Electronic Properties-Peter Grünberg Institute (PGI-6).

A novel quantum material PtTe₂ is used to establish the connection between ARPES spin textures and initial state spin textures. PtTe₂ is predicted to host Dirac type-II fermions and a number of application-relevant properties. The crystal structure of the most stable 1T-PtTe₂ polytype is trigonal, belongs to the space group 164 (P3m1), and exhibits 3-fold mirror planes and inversion symmetry. Since bulk 1T-PtTe₂ is both inversion-symmetric and non-magnetic, no bulk spin-polarized bands are allowed due to the Kramers degeneracy. At the surface, spin polarization is expected due to the broken inversion symmetry, however, it must obey the mirror and time-reversal symmetries.

We measured the dependence of spin-polarization on the symmetries of the ARPES experiment. This is performed in two geometries, with the reaction plane parallel to K-Γ-K and M-Γ-M reciprocal directions, i.e. either along or orthogonal to the crystal mirror plane. The measured spin texture is symmetric when the reaction plane is parallel to K-Γ-K. However, we could see asymmetries in the spin texture when the reaction plane is parallel to M-Γ-M. Such asymmetries are not allowed in the initial state and illustrate the mechanism of geometry-induced spin filtering in ARPES.