Realization of the Bonding Limit of Monatomic-Scale Quantum Wires by Mechanical Manipulation

Ideal monatomic-scale quantum wires usually exhibit perfect physical properties but suffer from unstable atomic bonding. Research on silicon atomic chains has focused on predicting the possibility of mechanical bonding rather than on its controllability. Here, molecular dynamics simulations show that the mechanical bonding enables the silicon atomic chain to realize the monatomic bonding limit of ∼99.9% silicon atoms, and such special bonding controllability makes the silicon wire exhibit ∼300% uniform elongation and the tensile bond strength of ∼2.0 GPa. The monatomic bonding stability originates from microstructural reconstruction of crystalline silicon induced by low-coordinated surface atoms. With the same tensile loading for crystalline diamond and germanium, it is further confirmed that the atomic bonding energy dominates the mechanical bonding stability of the monatomic-scale silicon wire and its bonding reliability. The proposed fabrication strategy for the silicon atomic chain in this work provides a platform to study the structural operability and bonding controllability of the monatomic-scale silicon quantum wire.