Dresden 2026 – scientific programme

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

O: Fachverband Oberflächenphysik

O 59: 2D Materials: Electronic structure, excitations, etc. II (joint session O/HL/TT)

O 59.1: Talk

Wednesday, March 11, 2026, 10:30–10:45, TRE/MATH

Polarons in epitaxial single-layer MnBr₂ — •Affan Safeer, Oktay Güleryüz, Guangyao Miao, Wouter Jolie, Thomas Michely, and Jeison Fischer — II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany

We investigate polaron formation in insulating single-layer MnBr₂ grown by molecular beam epitaxy on three different substrates: graphene on Ir(110), graphene on Ir(111), and Au(111). The polaron number densities and species depend strongly on the underlying substrate, underscoring the crucial role of the substrate. Our findings show that modeling of polarons in such single-layer insulators in contact with conducting substrates must explicitly include the substrate. For MnBr₂ grown on graphene/Ir(110), we identify four distinct polaron species, three of which closely resemble those reported for CoCl₂ on graphite. These polarons can be created, converted, and laterally manipulated by the STM tip when a tunneling current flows at suitable bias voltages. For graphene on Ir(110) as a substrate, mobile polarons in MnBr₂ are guided by the periodic potential imposed by the super-moiré pattern arising from the interaction of MnBr₂ with graphene and Ir(110).

Keywords: Polarons; MBE growth; Managnese dibromide; STM; 2D materials