Regensburg 2025 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

HL: Fachverband Halbleiterphysik

HL 40: 2D Semiconductors and van der Waals Heterostructures IV

HL 40.8: Talk

Wednesday, March 19, 2025, 17:30–17:45, H15

Magnetotransport in heterostructures of MBE-grown BS/BSTS and graphene — •Marina Marocko¹, Matthias Kronseder¹, Tobias Rockinger¹, Takashi Taniguchi², Kenji Watanabe², Dieter Weiss¹, and Jonathan Eroms¹ — ¹Institute of Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany — ²NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan

A number of novel phenomena have been observed or predicted in heterostructures of topological insulators and graphene. Similar to transition metal dichalcogenides, topological insulators are expected to dramatically increase the intrinsically very low spin-orbit coupling (SOC) in graphene due to the proximity effect. This opens the way for a range of potential applications, including a spin transistor based on the spin-orbit valve effect.

In our recent experiments, we used a thin MBE-grown film of BS/BSTS topological insulator to induce SOC in graphene. This material has the advantage of adjustable stoichiometry and thus increased possibilities of band structure engineering. The SrTiO3 substrate used for the MBE growth of BS/BSTS also serves as a gate dielectric.

Magnetotransport measurements at 1.7K show a very distinct and narrow weak antilocalization peak around zero magnetic field, which is a sign of induced SOC in graphene. The fitting procedure yields approximate values of the Rashba and valley-Zeeman spin-orbit coupling. We discuss how the extracted SOC values compare with theoretical predictions.

Keywords: graphene; topological insulator; proximity effect; spin-orbit coupling; weak antilocalization