Photoelectron spin polarization in the Bi2Te3(0001) topological insulator: Initial- and final-state effects in the photoemission process

Seibel, Christoph; Braun, Jürgen; Maaß, Henriette; Bentmann, Hendrik; Minár, Jan; Kuznetsova, Tatyana V.; Kokh, Konstantin A.; Tereshchenko, Oleg E.; Okuda, Taichi; Ebert, Hubert and Reinert, Friedrich (2016): Photoelectron spin polarization in the Bi2Te3(0001) topological insulator: Initial- and final-state effects in the photoemission process. In: Physical Review B, Vol. 93, No. 24, 245150

Abstract

The photoelectron spin polarization in angle-resolved photoemission from the topological surface state in Bi2Te3(0001) has been investigated in a combined experimental and theoretical study. Our measurements show significant photon-energy-dependent deviations in the three-dimensional spin polarization of the photoelectron when compared to the expected intrinsic spin polarization of the surface state. The experimental observations are in line with relativistic one-step photoemission calculations. Our theoretical analysis confirms that spin-orbit coupling in the initial-state wave functions in combination with the dipole selection rules strongly influences the photoelectron spin polarization. Furthermore, spin-dependent final-state effects are found to influence the spin polarization significantly. A quantitative access to the three-dimensional spin-polarization vector in topological insulators is thus challenged by a complex interplay of initial-and final-state effects in the photoemission process.

• Item Type: Journal article
• Faculties: Chemistry and Pharmacy > Department of Chemistry
• Subjects: 500 Science > 540 Chemistry
• ISSN: 2469-9950
• Language: English