Transformation Electronics: Tailoring Electron's Effective Mass
  The speed of integrated circuits is ultimately limited by the mobility of electrons or holes, which depend on the effective mass in a semiconductor. Here, building on an analogy with electromagnetic metamaterials and transformation optics, we describe a new transport regime in a semiconductor superlattice characterized by extreme anisotropy of the effective mass and a low intrinsic resistance to movement - with zero effective mass - along some preferred direction of electron motion. We theoretically demonstrate that such regime may permit an ultra fast, extremely strong electron response, and significantly high conductivity, which, notably may be weakly dependent on the temperature at low temperatures. These ideas may pave the way for faster electronic devices and detectors and new functional materials with a strong electrical response in the infrared regime. 
Mario G. Silveirinha, Nader Engheta
cond-mat.mes-hall