@article{Kudin2021spqeo24n1p056,
  title = {Surface structure of Gd20Co80 alloy},
  author = {Kudin, V.G. and Rozouvan, S.G. and Staschuk, V.S.},
  journal = {Semiconductor Physics, Quantum Electronics \& Optoelectronics},
  volume = {24},
  number = {1},
  pages = {56--63},
  year = {2021},
  doi = {10.15407/spqeo24.01.056},
  url = {https://doi.org/10.15407/spqeo24.01.056},
  abstract = {Gd 20 Co 80 alloy was studied applying experimental methods of spectral ellipsometry, atomic force and scanning tunneling microscopy. The experimental results exhibit the eutectic two-phase structure of this alloy. Clusters of a phase with a lower content had a lesser concentration of free carriers, which resulted in smaller tunnel currents during the measurements. To analyze the experimental data, a theoretical approach was developed, which was based both on the quantum-mechanical methods of configurational interaction and on three-diagonal Toeplitz matrices formalism. This approach allowed us to describe in detail the energy bands formation process in solid clusters with a relatively small quantity of atoms, which as a consequence enabled to describe the Shockley surface states as well as the existence of a surface layer with partially formed energy bands. Spectral-ellipsometric measurements of Gd 20 Co 80 alloy thin films confirmed a significant difference between the measured optical constants for 20-nm thick films and larger films. Quantum-mechanical molecular calculus allowed to obtain optical constants for several supercells of Gd-Co chemical compounds and confirmed the acquired experimental and theoretical results.},
  keywords = {gadolinium cobalt alloy, Shockley surface states, configuration interaction}
}