SPIN SPLITTING AND WEAK-LOCALIZATION IN (110)GAAS ALXGA1-XAS QUANTUM-WELLS/

We investigate both theoretically and experimentally the spin-orbit ef fects on the weak localization in a (110) GaAs two-dimensional electro n gas. We analyze the role of two different terms in the spin splittin g of the conduction band: the Dresselhaus terms, which arise due to th e lack of inversion center in the bulk GaAs, and the Rashba terms, whi ch are caused by the asymmetry of the quantum well. It is shown that i n A(3)B(5) quantum wells the magnetoresistance due to the weak localiz ation depends qualitatively on the orientation of the well. In particu lar, it is demonstrated that the (110) geometry has a distinctive feat ure that in the absence of the Rashba terms the ''antilocalization'' e ffect, i.e., the positive magnetoresistance, does not exist. Calculati on of the weak antilocalization magnetoresistance is found to be in ex cellent agreement with experiments.