悬浮纳米金属丝体系电导率的蒙特卡罗模拟  

Conductivity of Nanowires-suspended Systems:a Monte Carlo Study

作　　者：张婷[1] HOLGER Merlitz 林海[1] 吴晨旭[1] 

机构地区：[1]厦门大学物理学系理论与天体物理研究所软物质研究室,福建厦门361005

出　　处：《厦门大学学报（自然科学版）》2007年第4期482-486,共5页Journal of Xiamen University：Natural Science

基　　金：国家自然科学基金(10225428;90206039;20021002)资助

摘　　要：利用蒙特卡罗方法研究纳米金属丝悬浮于弱导电介质中时体系的电导率.由于该导电体系与扩散体系存在一一对应关系,可将导电体系转化为扩散体系,利用扩散模型模拟体系的扩散运动,以便分析单粒子系统和多粒子系统扩散系数的变化规律.模拟结果表明,在分布于介质中的金属丝之间无相互接触的条件下,悬浮金属丝体系电导率随金属丝导电性的增加呈现常数、线形增长、常数的变化规律;金属丝浓度很低时,电导率呈常数的范围略小于理论预测;金属丝浓度很高时体系发生渗流,电导率仅与金属丝电导率有关.The macroscopic conductivity of a composite of straight conducting wires,suspended isotropically in a poorly conducting medium,was studied using Monte-Carlo simulations. In order to analyze the scaling of the macroscopic diffusion coefficient and compare it with recent theoretical predictions.the authors translated the conductivity model to the diffusion model on the basis of the analogue between these two approaches and simulated the movement of a random walker inside the suspension for various system parameters,like wire density and wire conductivity. The results indicate that the macroscopic conductivity of the suspension is a constant at low wire conductivity,increases linearly at low-to moderate wire conductivity,and approaches a plateau at very high wire conductivities. Low wire concentration leads to a macroscopic conductivity of the suspension lower than theoretical prediction,while high wire concentration results in a percolation of the system related to the wire conductivity.

关 键 词：扩散系数 随机行走 纳米金属丝 电导率 

分 类 号：O487[理学—固体物理] O552.2[理学—物理]