GIANT FIELD-INDUCED VARIATION OF THE CYCLOTRON MASS IN COUPLED 2-DIMENSIONAL ELECTRON GASES

The cyclotron mass mc is calculated in coupled double quantum wells with in-plane magnetic fields (B). The shape of the Fermi surface varies continuously due to the partial minigap formed by the B-induced anticrossing of the two quantum-well energy-dispersion curves. In two dimensions, mc is shown to be proportional to the density of states at the Fermi surface. Sharp B-dependent structures arising from abrupt orbit changes near the gap are obtained for mc in excellent agreement with recent data, confirming recently proposed Fermi surfaces. Additional effects are predicted. © 1995 The American Physical Society.