Zero-resistance state of two-dimensional electrons in a quantizing magnetic field

Abstract

When the Fermi level is pinned in the energy gap between two Landau levels of two-dimensional electrons, the response of electrons in the completely filled levels to an electric field is a dissipation-free Hall current perpendicular to the field. Our low-temperature measurements on GaAs-${\mathrm{Al}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ heterojunctions give an upper limit for the resistance along the current path of ${\rho }_{\mathrm{xx}}\lesssim 5\times {10}^{-7\mathrm{}}$ Ω/□ which corresponds to a three-dimensional resistivity of $\rho <~5\times {10}^{-13\mathrm{}}$ Ω cm. This resistivity is more than one order of magnitude lower than the resistivity of any nonsuperconducting material.