Quantum conductance oscillation in linear monatomic silicon chains

•The conductance oscillates with a period of two atoms as the number of atoms in the silicon atomic chain is varied.•The transport channel is mainly contributed by px and py orbital electrons of silicon atoms.•The even–odd oscillation is robust under external voltage up to 1.2 V.

The conductance of linear silicon atomic chains with n=1–8 atoms sandwiched between Au electrodes is investigated by using the density functional theory combined with non-equilibrium Green's function. The results show that the conductance oscillates with a period of two atoms as the number of atoms in the chain is varied. We optimize the geometric structure of nanoscale junctions in different distances, and obtain that the average bond-length of silicon atoms in each chain at equilibrium positions is 2.15±0.03 Å. The oscillation of average Si–Si bond-length can explain the conductance oscillation from the geometric structure of atomic chains. We calculate the transmission spectrum of the chains in the equilibrium positions, and explain the conductance oscillation from the electronic structure. The transport channel is mainly contributed by px and py orbital electrons of silicon atoms. The even–odd oscillation is robust under external voltage up to 1.2 V.

Graphical abstractLinear silicon atomic chains with n=1–8 atoms sandwiched between Au electrodes. The conductance oscillates with a period of two atoms as the number of atoms in the chain is varied. The even–odd oscillation is robust under external voltage up to 1.2 V.Figure optionsDownload full-size imageDownload as PowerPoint slide