单分子磁体的输运电流噪声特性研究

项目名称： 单分子磁体的输运电流噪声特性研究

项目编号： No.11204203

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 薛海斌

作者单位： 太原理工大学

项目金额： 25万元

中文摘要： 鉴于单分子磁体在分子自旋电子学和电子信息技术领域的应用，其量子输运在实验和理论上引起人们的广泛关注，但相关研究主要集中在平均电流上。另一方面，从基础研究和应用的角度来说，仅仅知道其电流特性是不够的，尤其是在单分子磁体系统中电荷涨落对其量子输运有重要影响，而电子全计数统计和有限频率噪声可以提供比平均电流和散粒噪声更多的关于系统微观机制的信息。本项目首先发展在共隧穿极限下的四阶粒子数分辨量子主方程，然后基于此方法研究单分子磁体系统的库仑相互作用、横向各向异性、易轴与磁场的夹角、传导电子与分子大自旋的耦合强度、外加门电压、电极的不对称耦合等对其前三阶电流累积矩，即平均电流、散粒噪声、偏斜度，以及有限频率电流噪声特性的影响。探索加强或抑制单分子磁体电流噪声，特别是加强电流超泊松噪声的可能方法，并揭示其内禀量子特性与高阶电流累积矩和有限频率噪声之间的关系，为其在单分子量子器件方面的应用提供理论依据。

中文关键词： 单分子磁体；全计数统计；超泊松噪声；量子相干性；非马尔科夫效应

英文摘要： Electron transport through single-molecule magnet (SMM) has attracted considerable attention experimentally as well as theoretically due to the hope of applications in molecular spintronics and quantum information technology. These investigations focused on the differential conductance or average current.On the other hand, it is not enough just to know that the current-voltage characteristics of the SMM system from the fundamental research and applied point of view, and the charge fluctuation especially plays an important role in the electron transport of SMM. Full counting statistics and finite-frequency current noise can provide deep insight into the nature of transport mechanisms which are not accessible by the average current and shot noise measurements. In this project, first of all we develop an efficient fourth-order particle-number-resolved quantum master equation in the sequential and cotunneling regimes, then theoretically study the current noise properties of electron transport through a SMM based on the particle-number-resolved master equation approach. We put emphasis on the effects of the Coulomb interaction between two electrons in the lowest unoccupied molecular orbital, the transverse anisotropy, the angle between the external magnetic field and easy-axis of the SMM, the exchange coupling betw

英文关键词： Single-molecule magnet；magnet;Full counting statistics；Super-Poissonian noise；quantum coherence；Non-Markovian effects