title: Direct observation of liquid-like behavior of a single Au grain boundary.
abstract: Behavior of matter at the nanoscale differs from that of the bulk due to confinement and surface effects. Here, we report a direct observation of liquid-like behavior of a single grain boundary formed by cold-welding Au nanoparticles, 40 nm in size, by mechanical manipulation in situ TEM. The grain boundary rotates almost freely due to the free surfaces and can rotate about 90 degrees. The grain boundary sustains more stress than the bulk, confirming a strong bonding between the nanoparticles. Moreover, this technique allows the measurement of the surface diffusion coefficient from experimental observations, which we compute for the Au nanoparticles. This methodology can be used for any metal, oxide, semiconductor or combination of them.
authors.affiliation: Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, USA.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Casillas
authors.forename: Arturo
authors.initials: A
authors.lastname: Ponce
authors.forename: J Jesús
authors.initials: JJ
authors.lastname: Velázquez-Salazar
authors.forename: Miguel
authors.initials: M
authors.lastname: José-Yacamán