Conductance Modulation in Double Quantum Wells Due to Magnetic Field-Induced Anticrossing

Abstract

We observe a strong modulation of the low temperature in-plane conductance ${G}_{\ensuremath{\parallel}}$ of coupled quantum wells (QW's) by an in-plane magnetic field ${B}_{\ensuremath{\parallel}}$ and attribute this to an anticrossing of the two QW dispersion curves. The anticrossing produces a partial energy gap, yielding large, ${B}_{\ensuremath{\parallel}}$-tunable distortions in the Fermi surface and density of states. Sweeping ${B}_{\ensuremath{\parallel}}$ moves the energy gap through the Fermi level, with the upper and lower gap edges producing a sharp maximum and minimum in ${G}_{\ensuremath{\parallel}}$, in agreement with theoretical calculations. The gap energy is directly determined from the data.