Depth-resolved transport measurements and atom-probe tomography of heterogeneous, superconducting Ge:Ga films
Depth-resolved transport measurements and atom-probe tomography of heterogeneous, superconducting Ge:Ga films
Heera, V.; Fiedler, J.; Naumann, M.; Skrotzki, R.; Kölling, S.; Wilde, L.; Herrmannsdörfer, T.; Skorupa, W.; Wosnitza, J.; Helm, M.
Abstract
Ge films with a mean Ga content of about 8 at.% and 1 at.% hole concentration can be fabricated by ion implantation and subsequent flash-lamp annealing. The Ge:Ga films become superconducting below critical temperatures in the range between 1 and 2 K depending on the film resistance. The change of the macroscopic transport properties during step-wise surface etching can be described by a homogeneously doped layer model. However, the Ga distribution is extremely heterogeneous on the nanoscale. Atom-probe tomography analyses reveal the presence of Ga-rich precipitates with Ga clusters up to 10,000 atoms. Since no percolating Ga cluster exists, it can be supposed that the heavy doping of Ge enables a coherent superconducting state via the proximity effect.
Keywords: Ga ion implantation; flash-lamp annealing; superconducting Ge:Ga; inhomogeneous superconductor; hole doping; Ga cluster
Beteiligte Forschungsanlagen
- Hochfeld-Magnetlabor (HLD)
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 19152) publication
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Superconductor Science and Technology 27(2014), 055025
DOI: 10.1088/0953-2048/27/5/055025
Cited 8 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-19152