Phys.org  April 9, 2020 The underlying principle of ratcheting is to convert a fluctuating, unbiased force into unidirectional motion. A team of researchers in the US (University of North Carolina, Vanderbilt University, Duke University) reports the ratcheting of electrons at room temperature using a semiconductor nanowire with precisely engineered asymmetry. Modulation of the nanowire diameter creates a cylindrical sawtooth geometry with broken inversion symmetry on a nanometer-length scale. In a two-terminal device, this structure responded as a three-dimensional geometric diode that funnels electrons preferentially in one direction through specular reflection of quasi-ballistic electrons at the nanowire surface. The ratcheting effect […]