Spin precession observation in quantum corrections to resistance of Si 0:7 Ge 0:3 =Si 0:2 Ge 0:8 heterostructure with 2DHG

Abstract The two-dimensional hole gas (2DHG) magnetoresistivity of a Si0:7Ge0:3=Si0:2Ge0:8 heterostructure in a wide range of temperatures T = 0:335-20 K and transport currents I = 100-50 A is measured. In the vicinity of zero magnetic ÿeld, a sharp and positive in sign feature on smooth negative magnetoresistance is observed at the lowest temperatures. The amplitude of this feature quickly fades with increasing temperature and transport current. For the analysis of the experimental data the theory of weak localization for 2DHG is applied. The values of so and tr obtained are used for the ÿrst time to deÿne zero magnetic ÿeld splitting in the hole energy spectrum for a Si0:7Ge0:3=Si0:2Ge0:8 heterostructure: = 2:97 meV.