Huang Jing, Li Qunxiang, Ren Hao, Su Haibin, Shi Q W, Yang Jinlong
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
J Chem Phys. 2007 Sep 7;127(9):094705. doi: 10.1063/1.2770733.
The electronic transport properties and switching mechanism of single photochromic diarylethene derivatives sandwiched between two gold surfaces with closed and open configurations are investigated by a fully self-consistent nonequilibrium Green's function method combined with density functional theory. The calculated transmission spectra of two configurations are strikingly distinctive. The open form lacks any significant transmission peak within a wide energy window, while the closed structure has two significant transmission peaks on both sides of the Fermi level. The electronic transport properties of the molecular junction with closed structure under a small bias voltage are mainly determined by the tail of the transmission peak contributed unusually by the perturbed lowest perturbed unoccupied molecular orbital. The calculated on-off ratio of currents between the closed and open configurations is about two orders of magnitude, which reproduces the essential features of the experimental measured results. Moreover, we find that the switching behavior within a wide bias voltage window is extremely robust to both substituting F or S for H or O and varying end anchoring atoms from S to Se and Te.
采用完全自洽的非平衡格林函数方法结合密度泛函理论，研究了夹在两个具有闭合和开放构型的金表面之间的单光致变色二芳基乙烯衍生物的电子输运性质和开关机制。两种构型的计算透射光谱显著不同。开放形式在宽能量窗口内没有任何明显的透射峰，而闭合结构在费米能级两侧有两个明显的透射峰。在小偏压下，具有闭合结构的分子结的电子输运性质主要由受扰最低未占分子轨道异常贡献的透射峰尾部决定。计算得到的闭合和开放构型之间的电流开/关比约为两个数量级，再现了实验测量结果的基本特征。此外，我们发现，在宽偏压窗口内的开关行为对于用F或S取代H或O以及将末端锚定原子从S变为Se和Te都具有极强的稳定性。
