Weak antilocalization in quantum wells in tilted magnetic fields

Weak antilocalization is studied in an ${\mathrm{In}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ quantum well. Anomalous magnetoresistance is measured and described theoretically in fields perpendicular, tilted, and parallel to the quantum well plane. Spin and phase-relaxation times are found as functions of temperature and parallel field. It is demonstrated that spin dephasing is due to the Dresselhaus spin-orbit interaction. The values of electron spin-splittings and spin-relaxation times are found in the wide range of two-dimensional density. Application of in-plane field is shown to destroy weak antilocalization due to competition of Zeeman and microroughness effects. Their relative contributions are separated, and the values of the in-plane electron $g$ factor and characteristic size of interface imperfections are found.