Spin-charge separation in bipolar spin transport in (111) GaAs quantum wells

Abstract

We present a microscopic theory for transport of the spin polarized charge density wave with both electrons and holes in the (111) GaAs quantum wells. We analytically show that, contradicting to the commonly accepted belief, the spin and charge motions are bound together only in the fully polarized system but can be separated in the case of low spin polarization or short spin lifetime even when the spatial profiles of spin density wave and charge density wave overlap with each other. We further show that, the Coulomb drag between electrons and holes can markedly enhance the hole spin diffusion if the hole spin motion can be separated from the charge motion. In the high spin polarized system, the Coulomb drag can boost the hole spin diffusion coefficient by more than one order of magnitude.

Ehrlich-Schwöbel effect on the growth dynamics of GaAs(111)A surfaces

“…Amongst crystalline surfaces the (111) it's the one that has gathered more attention in the last years, especially for what concerned the optoelectronic applications of III-V semiconductors. Its physical and geometrical characteristics, in fact, are particularly suitable for devices as high mobility transistors (HMT) [1][2][3] and quantum well (QW) intersubband photodetectors 4 , but also for the feasible implementation of a new generation of devices like the ones based on topological insulators 5 , spintronics [6][7][8][9][10] and entangled photons [11][12][13][14][15][16][17] However, although high control on surface growth phenomena is a fundamental factor to avoid spurious and detrimental effects, like fine structure splitting for entangled photon generation or carriers mobility reduction for HMT, studies regarding the growth of this surface are few, lacking of an in depth description of growth mechanisms.…”

Coherent Acoustic Phonon and Its Chirping in Dirac Semimetal Cd 3 As 2

“…Topological quantum materials have recently attracted enormous research interests owing to their non-trivial electronic structures in momentum space, as well as potential applications in electronics and photonics devices. The theoretical predictions [1,2] and concomitant experimental investigations [3−6] of Dirac semimetal Cd 3 As 2 is a milestone in the development of topological quantum states. Early investigations focused mainly on the electronic, [4,7] magnetic [5] and transport properties.…”