First-Principles Study on Dynamic Electron-Transport Property through Low Dimensional System

Abstract

Recently, several first-principles studies on the electron-transport property of low dimensional nanomaterials, such as graphene sheets, nanotubes, and atomic or molecular chains, have been demonstrated. However, almost of them discuss the transport properties in the steady state, and there remains a lot of uncertainty on the dynamics of electrons flowing through the materials. In this study, we examined the dynamic transport properties of the nanomaterial suspended between semi-infinite electrodes. The dynamic behavior of electrons are simulated by the impulse response (IR) method [2] based on the real-space finite-difference approach [1] within the framework of the time-dependent density functional theory. It is reported that a phenyl chain absorbed on the gold substrate with thiol anchor groups exhibits two types of conduction channels in our previous study using a static transport property simulator [3]. Furthermore, adopting the IR method to phenyl chain systems, we found one channel can be ignored at a finite temperature since the response time of the channel is quietly slow (Fig. 1) compared with the period of intramolecular vibration mode at ~THz. Other applications of the IR method will be presented in the conference. Static IR