@article{MuellerSpriestersbachMinetal.2022, author = {M{\"u}ller, S. and Spriestersbach, F. and Min, C.-H. and Fornari, C. I. and Reinert, F.}, title = {Molecular beam epitaxy of TmTe thin films on SrF\(_{2}\) (111)}, series = {AIP Advances}, volume = {12}, journal = {AIP Advances}, number = {2}, doi = {10.1063/5.0083276}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300876}, year = {2022}, abstract = {The odd parity nature of 4f states characterized by strong spin-orbit coupling and electronic correlations has led to a search for novel topological phases among rare earth compounds, such as Kondo systems, heavy Fermions, and homogeneous mixed-valent materials. Our target system is thulium telluride thin films whose bandgap is expected to be tuned as a function of lattice parameter. We systematically investigate the growth conditions of TmxTey thin films on SrF\(_{2}\) (111) substrates by molecular beam epitaxy. The ratio between Te and Tm supply was precisely tuned, resulting in two different crystalline phases, which were confirmed by x-ray diffraction and x-ray photoemission spectroscopy. By investigating the crystalline quality as a function of the substrate temperature, the optimal growth conditions were identified for the desired Tm1Te1 phase. Additional low energy electron diffraction and reflective high energy electron diffraction measurements confirm the epitaxial growth of TmTe layers. X-ray reflectivity measurements demonstrate that homogeneous samples with sharp interfaces can be obtained for varied thicknesses. Our results provide a reliable guidance to prepare homogeneous high-quality TmTe thin films and thus serve as a basis for further electronic investigations.}, language = {en} } @article{FornariRapplMorelhaoetal.2016, author = {Fornari, C. I. and Rappl, P. H. O. and Morelhao, S. L. and Peixoto, T. R. F. and Bentmann, H. and Reinert, F. and Abramof, E.}, title = {Preservation of pristine Bi\(_2\)Te\(_3\) thin film topological insulator surface after ex situ mechanical removal of Te capping layer}, series = {APL Materials}, volume = {4}, journal = {APL Materials}, doi = {10.1063/1.4964610}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164468}, pages = {106107}, year = {2016}, abstract = {Ex situ analyses on topological insulator films require protection against surface contamination during air exposure. This work reports on a technique that combines deposition of protective capping just after epitaxial growth and its mechanical removal inside ultra-high vacuum systems. This method was applied to Bi2Te3 films with thickness varying from 8 to 170 nm. Contrarily to other methods, this technique does not require any sputtering or thermal annealing setups installed inside the analyzing system and preserves both film thickness and surface characteristics. These results suggest that the technique presented here can be expanded to other topological insulator materials.}, language = {en} }