CAREER: Structural Helicity in Ultra-Thin Alloy Nanowires

本学院早期职业发展（Career）项目的研究目标是研究直径为几纳米及以下的合金纳米线的尺寸、结构和成分之间的相互作用。纳米线具有很高的机械强度和弹道导电性，这使其成为纳米级电路中的连接器或纳米机电器件中的元件。在纳米器件中的实际应用需要合理控制纳米线的结构、电子和机械性能。合金化和掺杂是实现这种控制的直接手段。本研究将采用遗传算法和分子动力学模拟来研究合金纳米线的结构和性能，特别是检查这些金属线表现出螺旋结构的参数制度。交付成果包括各种尺寸和成分体系的稳定性条件，用于与实验比较的电子显微镜特征模拟，纳米线的机械性能研究，特别是与螺旋结构相关的纳米线合金的电导特征。如果成功，这项研究将有助于确定合金在特定纳米线系统中持续存在的极限，并将深入了解合金在纳米尺度上改善材料性能所提供的机会。研究结果可用于设计各种利用螺旋结构的纳米机电系统，以提高其灵敏度和功能。本项目将对研究生进行培训，研究成果将纳入PI教授的研究生课程。此外，还将为本科生创造研究机会。我们将开设一门新课程，让学生熟悉纳米力学和材料科学的先进数值和模拟技术。PI将参与若干国际合作，并与女性工程师协会和科罗拉多矿业学院的少数民族工程项目开展大量培训和推广活动。

The research objective of this Faculty Early Career Development (CAREER) project is to investigate the interplay between size, structure and composition for alloy nanowires with diameters of several nanometers and below. Nanowires can exhibit high mechanical strength and ballistic conductance, which makes them appealing as connectors in nanoscale circuits or as elements in nano-electromechanical devices. Practical use in nanodevices requires a rational control of the structural, electronic, and mechanical properties of the nanowires. Alloying and doping are direct means to exert such control. This research will employ genetic algorithms and molecular dynamics simulations to study the structure and properties of alloy nanowires, and in particular to examine the parameter regimes in which these wires exhibit structural helicity. Deliverables include conditions of stability for various size and composition regimes, simulations of electron microscopy signatures for comparison with experiments, studies of mechanical properties of nanowires especially those associated with helical structures, and conductance signatures of the nanowire alloys. If successful, this research will help determine the limits in which alloying persists in specific nanowire systems, and will give insight into the opportunities offered by alloying to improve material properties at nanoscale. The results can be useful in the design of various nano-electromechanical systems that exploit the helical structure to improve their sensitivity and functionality. Graduate student training will be provided during this project, and research results will be incorporate into graduate classes taught by the PI. In addition, opportunities for undergraduate research will be created. One new course will be developed in which students will become familiar with advanced numerical and simulation techniques in nanomechanics and materials science. The PI will participate in several international collaborations, and in ample activities of training and outreach with the Society of Women Engineers and the Minority Engineering Program at Colorado School of Mines.