SPIN DYNAMICS IN SEMICONDUCTOR NANOSTRUCTURES

Much attention has been devoted to the electron spin dynamics in semiconductors for the past three decades [1,2]. Especially, recent experiments have shown extremely long spin lifetime (up to hundreds of nanoseconds) in n-type bulk zinc-blende semiconductors (such as GaAs) [4-5]. Moreover, more investigations have been performed on various low dimensional systems [6]. The spin diffusion/transport has also been studied experimentally, and very long spin injection length are reported [7]. These findings show the great potential for using the spin degree of freedom in place of, or in addition to, the charge degree of freedom for device application such as qubits and spin transistors. A thorough understanding of the spin relaxation/dephasing (R/D) in the spin precession and spin diffusion/transport is essential for such applications. It is understood that the D'ayakonov-Perel' (DP) mechanism is the leading spin R/D mechanism in n-type zinc-blende semiconductors [8]. Many theoretical works have been carried out to study the spin relaxation time in various systems [1,9] based on the single-particle formula [1]