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

We have investigated the weak-localization magnetoresistance of electrons i n a m-V semiconductor quantum well (SQW) under a magnetic field applied par allel to interfaces, so it interacts only with the electron spins through t he Zeeman term in the Hamiltonian. The effect of crystal orientation ih con nection to the spin-orbit coupling in the conduction hand 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 b e very sensitive to the crystal orientation as well as to the direction of the magnetic field. The magnetoresistance is positive in general, except fo r certain cases of [011]-oriented SQW, The magnetoresistance saturates at h igh-magnetic field, where its anisotropy still remain;. We have shown that the anisotropy of the magnetoresistance is a direct measure of the ratio be tween the Bychkov-Rashba and Dresselhaus terms of the spin-orbit coupling. The. effect of interface imperfections on the magnetoresistance has also be en analyzed in detail. [S0163-1829(99)03208-7].