Nanowerk December 16, 2020
In quantum anomalous Hall (QAH) insulators, electron flow is constrained to the edges, and electrons on one edge can only go in one direction and those on the other edge can only go the opposite direction. In prior studies, the QAH effect had been experimentally realized only in materials where the Chern number had a value of 1, essentially with a single two-lane highway for electrons. They observed some dissipation of current at connection points between QAH insulators and metallic electrodes, which occurs in the form of heat. However, by increasing the thickness of the QAH insulator layers, or by manipulating the concentration of magnetic doping in the QAH layer, they could tune the Chern number of the sample. In the future, they hope to develop a technique to tune the Chern number of an already fabricated sample, for “real-time” control of the electron traffic in an information highway. According to the researchers through creative material synthesis, they envision scenarios that might help us realize these effects under technologically relevant conditions…read more. TECHNICAL ARTICLEÂ
Observations of the high-C QAH effect in magnetic–undoped topological insulator multilayer structures. Credit: Nature volume 588, pages419–423(2020)