Al、P掺杂Si原子链电子输运性质的第一性原理计算

摘要

Electron transport properties of linear silicon atomic chains, which is coupled between two semi-infinite Au (100) leads through a sulfur atom, was calculated from first principles using density functional theory combined with non-equilibrium Green's function method. The results show that equilibrium conductance is 1.237 G0, and electrons are trans?ported throughπbond formed by p electrons in silicon atomic chain. Doping aluminum atom in silicon atomic chain can weaken electron transport properties of silicon chain. That makes resonant tunneling peak of LUMO in silicon atomic chain away from Fermi surface, the equilibrium conductance decrease to 0.491 G0. However, doping phosphorus atom in silicon atomic chain can improve electron transport properties. That make resonant tunneling peak of LUMO close to the Fermi surface, the equilibrium conductance increase to 1.624 G0.%运用密度泛函理论结合非平衡格林函数的方法对直线硅原子链及其分别掺杂Al、P原子的电子输运性质进行了第一性原理计算.结果发现未掺杂Si原子链的平衡电导为1.237 G0，电子主要通过p轨道电子形成的π键进行输运；掺杂Al能改变Si原子链的电子输运行为，使LUMO隧穿共振峰离费米面更远，平衡电导减小为0.491 G0；掺杂P原子使Si原子链的LUMO峰离费米面更近，平衡电导增加为1.621 G0，更有利于改善Si原子链的电子输运性能.