Superconductivity in single-crystalline aluminum- and gallium-hyperdoped germanium

Slawomir Prucnal, Viton Heera, René Hübner, Mao Wang, Grzegorz P. Mazur, Michał J. Grzybowski, Xin Qin, Ye Yuan, Matthias Voelskow, Wolfgang Skorupa, Lars Rebohle, Manfred Helm, MacIej Sawicki, Shengqiang Zhou

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10 Scopus citations


Superconductivity in group IV semiconductors is desired for hybrid devices combining both semiconducting and superconducting properties. Following boron-doped diamond and Si, superconductivity has been observed in gallium-doped Ge; however, the obtained specimen is in polycrystalline form [Phys. Rev. Lett. 102, 217003 (2009)10.1103/PhysRevLett.102.217003]. Here we present superconducting single-crystalline Ge hyperdoped with gallium or aluminum by ion implantation and rear-side flash lamp annealing. The maximum concentration of Al and Ga incorporated into substitutional positions in Ge is 8 times higher than the equilibrium solid solubility. This corresponds to a hole concentration above 1021cm-3. Using density functional theory in the local-density approximation and pseudopotential plane-wave approach, we show that the superconductivity in p-type Ge is phonon mediated. According to the ab initio calculations, the critical superconducting temperature for Al- and Ga-doped Ge is in the range of 0.45 K for 6.25at.% of dopant concentration, being in qualitative agreement with experimentally obtained values.
Original languageEnglish (US)
JournalPhysical Review Materials
Issue number5
StatePublished - May 9 2019


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