Quantum transport in In0.75Ga0.25As quantum wires

In addition to quantized conductance plateaus at integer multiples of 2e(2)/h, the differential conductance G=dI/dV shows plateaus at 0.25(2e(2)/h) and 0.75(2e(2)/h) under applied source-drain bias in In0.75Ga0.25As quantum wires defined by insulated split gates. This observation is consistent with a spin-gap model for the 0.7 structure. Using a tilted magnetic field to induce Landau level crossings, the g factor was measured to be similar to 9 by the coincidence method. This material, with a mobility of 1.8x10(5) cm(2)/V s at a carrier density of 1.4x10(11) cm(-2), may prove useful for further study of electron-electron interaction effects in quantum wires. (C) 2008 American Institute of Physics.