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HL: Fachverband Halbleiterphysik

HL 8: 2D Materials II (joint session HL/CPP)

HL 8.8: Talk

Monday, March 27, 2023, 17:00–17:15, POT 81

Electronic structures of twisted bilayer graphene and tungsten diselenide investigated by transferable tight-binding-models — •Xiaoyu Liu, Stefan Blügel, and Hyun-Jung Kim — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany

Since the discovery of intrinsic unconventional superconductivity in the Moiré superlattice from bilayer graphene stacked with a small twist angle, a new venue so-called twistronics has opened. Beyond graphene, transition metal dichalcogenides as a class of two-dimensional (2D) materials have attracted much attention due to their interesting optical properties. With the growing interest in 2D layered materials, accurate models describing the band structure and electronic properties of twisted bilayer graphene and tungsten diselenide are highly desirable. Here, we provide sets of parameters for the transferable tight-binding (TB) model, based on the Slater-Koster (SK) scheme with the exponential scaling law for the interlayer and overlap integral parameters. The workflow, to obtain transferable TB model parameters, is automatized by introducing global optimization methods such as particle swarm optimization (PSO) and conformational space annealing (CSA) methods. The fitness of the parameter set is assessed not only by comparing with ab-initio band energies, but also with its orbital similarity. Accurately produced electronic structures of twisted bilayers graphene and tungsten diselenide provide a chance to research their unique electronic and optical attributes.
Hyun-Jung Kim acknowledges support by the AvH Foundation.