Promotionsvortrag Physik: Proximity effects in intercalated epitaxial graphene on SiC: From charge neutrality, inter-layer Pb bands, and spin textures to Tb-induced doping beyond van Hove filling

Ankündigung des Promotionsvortrags von: Frau Bharti Matta

Intercalation of epitaxial graphene on silicon carbide (SiC) is a robust approach for modifying gra-phene's properties and stabilizing two-dimensional (2D) forms of elements at the graphene/SiC interface. Among the various elements explored as intercalants, Lead (Pb) has attracted particular interest due to its superconducting nature and strong intrinsic spin-orbit coupling (SOC), making it an excellent candidate for inducing similar proximity effects in graphene.

In my talk, I'll present a detailed investigation of the electronic structure of Pb-intercalated quasi-freestanding monolayer graphene on SiC using angle-resolved photoelectron spectroscopy (ARP-ES). The graphene π bands show near charge-neutrality, involving a combined charge transfer from both the interlayer Pb and SiC. The Pb-derived bands exhibit a metallic nature with a (1×1) registry with respect to SiC, corroborated by ARPES measurements in the repeated Brillouin zone of Pb. Light polarization-dependent ARPES measurements reveal a predominantly out-of-plane orbital character for the Pb bands, suggesting the possibility of interactions between the pz orbitals of the interlayer Pb and graphene, potentially contributing to proximity effects in graphene. Density functional theory calculations for a (1×1) Pb monolayer on SiC qualitatively corroborate these ob-servations.

Motivated by the prospect of SOC-driven effects, spin-resolved ARPES measurements were per-formed. These measurements reveal pronounced spin polarization in the Pb interlayer, along with a tangential spin texture in the momentum space. Notably, the graphene π bands also exhibit measurable spin polarization, which may be attributed to proximity-induced Rashba-type spin split-ting.

(Vortrag auf Englisch)

Dem Vortrag schließt sich eine Diskussion von 15 Minuten an. Vortrag und Diskussion sind öffentlich. Diesen Verfahrensteilen folgt ein nicht öffentliches Rigorosum von 45 Minuten.