EDGE-INDUCED MODIFICATION OF TUNNEL MIXING AND RESISTANCE RESONANCE IN DOUBLE-QUANTUM-WELL STRIPS

The electron spectrum and conductivity of a finite-width double-quantu m-well system (a DQW strip) are studied theoretically. The difference between the edge potentials for left and right wells modifies tunnel m ixing at the edges and causes redistribution of the wave function betw een the wells. As a result, the description of electronic eigenstates in the DQW strip changes essentially in comparison to the case of an i nfinite DQW plane. The edge effect significantly modifies the electric al conductivity of a DQW strip with nonsymmetric scattering when the w idth of the strip is less than the mean free path length of electrons. In particular, we find (i) the suppression of the resistance resonanc e peak, (ii) the asymmetry of this peak, and (iii) the oscillations of the resistivity upon the background of the peak. All these features a re manifestations of a quantum size effect in conductivity appearing w hen the strip width becomes comparable to the tunnel coherence length, the latter being essentially longer than the wavelength of electrons with Fermi energy. [S0163-1829(98)02019-0].