NUKFER

Novel sample environments and X-ray optics for in situ resonant nuclear scattering studies of geological, biological and nanotechnological iron-based materials

The aim of the NUKFER project is to obtain a comprehensive understanding of the changes in the phonon density of states of materials with orders of magnitude in the nanometer and subnanometer range and thus to gain control over the lattice dynamics on the nanometer scale. In order to achieve this goal, in-situ inelastic nuclear magnetic resonance scattering experiments with nano-focused X-rays are carried out on individual nano-objects on the Dynamics Beamline P01 at PETRA III. A compact ultra-high vacuum chamber, equipped with a nanoscanner and X-ray transparent beryllium windows has been specifically designed for the project. Combined with suitable Kirkpatrick-Baez-Optics this enables the investigation of individual nano-objects. A systematic investigation of the change in the Fe-partial phonetic density and the resulting thermoelastic properties is carried out on the model of individual, self-organized, metallic and semiconducting FeSi2 nanowires, nano-islands and nanoclusters with different sizes, shapes and crystal phases. Ab initio calculations carried out by a cooperation partner provide complementary understanding of the electronic properties and experimental results.

Fig. 1: the UHV chamber for in situ nuclear magnetic resonance scattering experiments on individual nano-objects. (A) UHV chamber with control units for pressure measurement, ion pump and bakeout unit, (B) rear side of the UHV chamber with Be window for diffracted outgoing X-rays, (C) front view with Be window for incident X-rays, (D) UHV chamber in a tailor-made heating jacket and (E) specially made sample holder mounted on the nanopositioning unit.

A systematic investigation of the change in the Fe-partial phonon density and the resulting thermoelastic properties is carried out on the model of individual, self-organized, metallic and semiconducting FeSi2 nanowires, nano-islands and nanoclusters with different sizes, shapes and crystal phases. Ab initio calculations carried out by a cooperation partner provide complementary understanding of the electronic properties and experimental results.

 

Fig. 2: UL: AFM images of the sample surface. LL: ab initio calculations of the element- and direction-specific PDOS for α-FeSi2. R: Measured PDOS of the nanostructures (black symbols), result of the modeling (red line with the respective polarization components (green and gray-dashed area).

 

Publications
  1. Lattice dynamics of endotaxial silicide nanowires., Kalt, J.; Sternik, M.; Krause, B.; Sergueev, I.; Mikolasek, M.; Merkel, D.; Bessas, D.; Sikora, O.; Vitova, T.; Göttlicher, J.; Steininger, R.; Jochym, P. T.; Ptok, A.; Leupold, O.; Wille, H.-C.; Chumakov, A. I.; Piekarz, P.; Parlinski, K.; Baumbach, T.; Stankov, S., 2020. Physical review / B, 102 (19), Art.-Nr.: 195414. doi:10.1103/PhysRevB.102.195414
  2. Lattice dynamics and polarization-dependent phonon damping in α-phase FeSi2 nanostructures., Kalt, J.; Sternik, M.; Krause, B.; Sergueev, I.; Mikolasek, M.; Bessas, D.; Sikora, O.; Vitova, T.; Göttlicher, J.; Steininger, R.; Jochym, P. T.; Ptok, A.; Leupold, O.; Wille, H.-C.; Chumakov, A. I.; Piekarz, P.; Parlinski, K.; Baumbach, T.; Stankov, S., 2020. Physical review / B, 101 (16), Art.-Nr.: 165406. doi:10.1103/PhysRevB.101.165406
  3. Lattice dynamics of epitaxial strain-free interfaces., Kalt, J.; Sternik, M.; Sergueev, I.; Herfort, J.; Jenichen, B.; Wille, H.-C.; Sikora, O.; Piekarz, P.; Parlinski, K.; Baumbach, T.; Stankov, S., 2018. Physical review / B, 98 (12), 121409(R). doi:10.1103/PhysRevB.98.121409
  4. Ab initio and nuclear inelastic scattering studies of Fe3Si/GaAs heterostructures., Sikora, O.; Kalt, J.; Sternik, M.; Ptok, A.; Jochym, P. T.; Łażewski, J.; Parlinski, K.; Piekarz, P.; Sergueev, I.; Wille, H.-C.; Herfort, J.; Jenichen, B.; Baumbach, T.; Stankov, S., 2019. Physical review / B, 99 (13), 134303. doi:10.1103/PhysRevB.99.134303
  5. Lattice dynamics of endotaxial silicide nanowires., Kalt, J.; Sternik, M.; Krause, B.; Sergueev, I.; Mikolasek, M.; Merkel, D.; Bessas, D.; Sikora, O.; Vitova, T.; Göttlicher, J.; Steininger, R.; Jochym, P. T.; Ptok, A.; Leupold, O.; Wille, H.-C.; Chumakov, A. I.; Piekarz, P.; Parlinski, K.; Baumbach, T.; Stankov, S., 2020. Physical review / B, 102 (19), Art.-Nr.: 195414. doi:10.1103/PhysRevB.102.195414
  6. A portable ultrahigh-vacuum system for advanced synchrotron radiation studies of thin films and nanostructures: EuSi₂ nano-islands., Ibrahimkutty, S.; Seiler, A.; Prüßmann, T.; Vitova, T.; Pradip, R.; Bauder, O.; Wochner, P.; Plech, A.; Baumbach, T.; Stankov, S., 2015. Journal of synchrotron radiation, 22 (1), 91–98. doi:10.1107/S1600577514019705
  7. When heat ceases to be a mystery, spintronics becomes more real
  8. Lattice dynamics of beta-phase FeSi2 nanorods J. Kalt, M. Sternik, B. Krause, I. Sergueev, M. Mikolasek, D. Bessas, O. Sikora, T. Vitova, J. Göttlicher, R. Steininger, P. T. Jochym, A. Ptok, O. Leupold, H.-C. Wille, A. I. Chumakov, P. Piekarz, K. Parlinski, T. Baumbach and S. Stankov Phys. Rev. B, in prep.