Dimer bond geometry in D/Ge(100)-(2×1): A low-energy electron-diffraction structure analysis

The asymmetry of the Ge dimer in the (2×1) reconstruction of Ge(100) is removed upon adsorption of deuterium D. The $R$-factor analysis indicates a slight remaining asymmetry which is attributed to the coexistence of bare and D-covered dimers. The Ge-Ge bond length of 2.4(2) Å in the dimer does not change within the error limits when compared to the clean surface. The D atoms bond on top of the Ge atoms, exhibiting a Ge-D bond length of 1.6(2) Å.