Une surstructure de α-Ge, type diamant, induite par un dopage d'antimoine

Abstract

Single crystals of antimony-doped germanium, Ge1–x Sb x+0.01 (x ≃ 0.0625), were grown by chemical transport reaction. The alloy crystallizes as a superstructure of diamond-type α-Ge. All atoms in the asymmetric unit lie on special positions and are characterized by strong covalent bonds. The antimony atoms substitute for one germanium atom at full occupancy at Wyckoff position 4a (site symmetry -43m), and are also at an adjacent tetrahedral interstitial site with partially occupation (16%) at position 4c (or 4d) (site symmetry -43m). The structural model does not show close Sb...Sb contacts, and suggests that the interstitial antimony atoms move between the two adjacent tetrahedral sites.