Regensburg 2016 – scientific programme

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DS: Fachverband Dünne Schichten

DS 5: Two-dimensional Materials
(Joint session of DS and HL, organized by HL)

DS 5.11: Talk

Monday, March 7, 2016, 12:45–13:00, H16

Theoretical studies of transition metal dichalcogenides for the use in electron holography — •Sven Borghardt¹, Zeila Zanolli⁴, Matthieu Verstraete³, Florian Winkler², Juri Barthel², Rafal Dunin-Borkowski², and Beata Kardynal¹ — ¹PGI-9, Forschungszentrum Jülich, Jülich, Germany — ²ER-C, Forschungszentrum Jülich, Jülich, Germany — ³PCPM, Université Catholique de Louvain, Louvain-la-Neuve, Belgium — ⁴PGI-2 and IAS, Forschungszentrum Jülich, Jülich, Germany

Few-layer transition metal dichalcogenides (TMDs) represent a new family of materials with promising properties for new optoelectronic nano-devices. Their well-known and tailorable thickness render them an ideal system for quantitative electron holography.

Here, we present the simulation of the effect of charge reorganisation due to bonding on the phase acquired by electrons passing through few layer TMD structures in electron holography experiments. This is done by simulating the phases for potentials from density functional theory calculations in comparison with ones obtained from the independent-atom approximation. The results show in an impressive way that neglecting the atomic bonding and the associated small change in the overall charge distribution leads to an overestimation of the average electron phase by approximately 5% for the analyzed materials. Comparison with experimental data confirms this conclusion.

Building on the results for pristine materials, we present calculations for single defects and heterostructures composed of different materials from the transtition-metal dichalcogenide family.