Quantum Corrections to Conductivity for Semiconductors with Various Structures

We study the magnetic field dependences of the conductivity in heavily doped, strongly disordered 2D quantum well structures within wide conductivity and temperature ranges. We show that the exact analytical expression derived in our previous paper [S. A. Alavi and S. Rouhani, Phys. Lett. A 320, 327 (2004)], is in better agreement with the existing equation, i.e., Hikami et al. expression [ Prog. Theor. Phys. 63, 707 (1980)] and Littman and Schmid expression [J. Low Temp. Phys. 69, 131 (1987)], with the experimental data even in low magnetic field for which the diffusion approximation is valid. On the other hand from theoretical point of view we observe that our equation is also rich because it establishes a strong relationship between quantum corrections to the conductivity and the quantum symmetry Su_q(2). It is shown that the quantum corrections to the conductivity is the trace of Green function made by a generator of Su_q(2) algebra. Using this fact we show that the quantum corrections to the conductivity can be expressed as a sum of an infinite number of Feynman diagrams.