Quantum diffusion in bilateral doped chains

In this paper, we quantitatively study the quantum diffusion in a bilateral doped chain, which is randomly doped on both sides. A tight binding approximation and quantum dynamics are used to calculate the three electronic characteristics: autocorrelation function C(t), the mean square displacement d(t) and the participation number P(E) in different doping situations. The results show that the quantum diffusion is more sensitive to the small ratio of doping than to the big one, there exists a critical doping ratio q0, and C(t), d(t) and P(E) have different variation trends on different sides of q0. For the self-doped chain, the doped atoms have tremendous influence on the central states of P(E), which causes the electronic states distributed in other energy bands to aggregate to the central band (E = 0) and form quasi-mobility edges there. All of the doped systems experience an incomplete transition of metal-semiconductor-metal. (condensed matter: structural, mechanical, and thermal properties)