Crystal anisotropy effects on the weak-localization magnetoresistance of a III-V semiconductor quantum well in a magnetic field parallel to interfaces

We have investigated the weak-localization magnetoresistance of electrons in a III-V semiconductor quantum well (SQW) under a magnetic field applied parallel to interfaces, so it interacts only with the electron spins through the Zeeman term in the Hamiltonian. The effect of crystal orientation in connection to the spin-orbit coupling in the conduction band has been analyzed. We have studied SQW samples with epitaxy growth direction along the [001], [011], and [111], crystal axes. The magnetoresistance has been found to be very sensitive to the crystal orientation as well as to the direction of the magnetic field. The magnetoresistance is positive in general, except for certain cases of [011]-oriented SQW. The magnetoresistance saturates at high-magnetic field, where its anisotropy still remains. We have shown that the anisotropy of the magnetoresistance is a direct measure of the ratio between the Bychkov-Rashba and Dresselhaus terms of the spin-orbit coupling. The effect of interface imperfections on the magnetoresistance has also been analyzed in detail.