碳鏈系統熱電效應的研究與設計分子轉子

Abstract

我們研究分子接面的電子傳輸性質與量子效應。以第一原理計算的方式，分別模擬了碳鏈系統與苯環分子直接與鉑電極連接的兩種系統。我們發現碳鏈系統中，Seebeck係數會隨著電極中間的碳原子數目的不同其正負號會有奇偶效應。而奇偶效應的原因為:當碳鏈中的碳數增加時，穿隧方程式在費米能階附近的斜率會變號。另外我們研究了苯環分子連接鉑電極系統，利用電流驅動不對稱苯環系統並結合鍵結的特性，使此系統產生旋轉。當電流通過傾斜苯環時，會在苯環上藉由電流感應產生力矩，結合鉑金屬鍵無方向性的特性，並且去計算電流密度的旋度不等於零，來證實苯環分子連接鉑電極系統是易於旋轉的，而產生一分子轉子。

we investigate the electron transport properties and quantum effects of nano-junction. By way of first-principles approaches, we have simulated two different systems. The first system is Carbon-atoms chains connecting bimetal junction, and the other one is benzene molecules which directly connect between two Pt electrodes. . In carbon-atoms chains system, we observe odd-even effects in the Seebeck coefficient of carbon-atom chains as the number of carbon atoms increases. The reason for the odd-even effects is that the tangent of transmission functions near the chemical potential change signs as the number of carbon atoms in the junction increases. In the metal-benzene-metal junction, using current to drive asymmetric benzene system with bonding characteristics make this system to produce rotation. When the current through the tilted benzene, torque on the benzene ring is induced by current .And combined with the non-directional bonding Characteristics of platinum metal and the non-zero curl of current density, we can confirm that benzene with platinum electrode system is easy to rotate and produced a molecular rotor.