Quantum effects in twinning boundary formation in Pb

The stratification of Pb nanoislands on the vicinal Si(7 7 10) surface into layers 2 nm thick, due to the quantization of the electronic spectrum, implies the formation of two-dimensional defects separating the layers. Energy balance of energy gain due to the quantum confinement effect and energy consume for a twinning boundary formation was determined using DFT simulations. It was established that established that the twin boundary is formed at the stage of growth of the next layer after the formation of a layer 2 nm thick, in which a standing wave of Fermi electrons is formed. On the surface of a thinner layer, where there is no standing electron wave, a perfect crystal structure grows. The formation of a twin boundary between layers 2 nm thick Pb begins with the formation of a rarefied atomic monolayer of pairs of atoms.