David B. Torrance, Baiqan Zhang, Tien Hoang and Phillip N. First School of Physics, Georgia Tech
Scanning tunneling microscope (STM) topograph of graphene growing over the top-corner of bunched atomic steps. The full step-bunch has a height of 15 nm. Tunneling spectroscopy shows strain that is largest at the red dot, and decays with distance from the edge (purple to blue dots).
Graphene grown on silicon carbide grows fastest near bunches of atomic steps. Arresting the growth at an early stage can leave stripes where ribbons of graphene grow like a carpet over the corner of a step-bunch. Along this corner, the electron states of graphene are found to be modified by strain. The discrete electron states created by this strain may some day find use as waveguides for electron matter waves, analogous to optical fibers for light.