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Seminar: Probing nanocrystalline grain dynamics in ruthenium dioxide nanowires

Time: 4:00pm, Thursday, June 8th, 2017

Location: Room 242, East 4 teaching building , Zijingang Campus

Sheng-Shiuan Yeh (葉勝玄)

Institute of Physics, national Chiao Tung University (台灣交通大學)


Abstract:

Dynamical structural defects exist naturally in a wide variety of solids (conductors and non-conductors). The entities of such dynamic objects fluctuate temporally and have been identified to be individual atoms. On the other hand, it is a long-standing question whether a nanocrystalline grain constituted of a large number of atoms can switch, as a whole, reversibly like a dynamical atomic defect (i.e., a two-level system). This is an emergent issue considering the current development of nanodevices with ultralow electrical noise, qubits with long quantu coherence time, and nanoelectromechanical system (NEMS) sensors with ultrahigh resolution. We demonstrate experimental observations o dynamic nanocrystalline grains which repeatedly switch between two or more metastable coordinate states. We study temporal resistance fluctuations in thin ruthenium dioxide (RuO2) metal nanowires and extract microscopic parameters including relaxation time scales, mobile grai sizes, and the bonding strengths of nanograin boundaries. Such material parameters are not obtainable by other experimental approaches. Our conception and electrical method can be used to infer rich information about the structural dynamics of a wide variety of nanodevices and new 2D materials.