Spin transport in undoped InGaAs/AlGaAs multiple quantum well studied via spin photocurrent excited by circularly polarized light.

Laipan Zhu,Wei Huang,Yu Liu,Yonghai Chen,Qing Wu,Yuan Li,Xudong Qin

doi:10.1186/s11671-015-1218-3

Abstract

The spin diffusion and drift at different excitation wavelengths and different temperatures have been studied in undoped InGaAs/AlGaAs multiple quantum well (MQW). The spin polarization was created by optical spin orientation using circularly polarized light, and the reciprocal spin Hall effect was employed to measure the spin polarization current. We measured the ratio of the spin diffusion coefficient to the mobility of spin-polarized carriers. From the wavelength dependence of the ratio, we found that the spin diffusion and drift of holes became as important as electrons in this undoped MQW, and the ratio for light holes was much smaller than that for heavy holes at room temperature. From the temperature dependence of the ratio, the correction factors for the common Einstein relationship for spin-polarized electrons and heavy holes were firstly obtained to be 93 and 286, respectively.

Highlights

Much attention has been given to semiconductor spintronics for the promising applications in information technology [1, 2]
We focused on the spectrum and temperature dependence of the transport properties corresponding to interband transitions in an undoped InGaAs/AlGaAs multiple quantum well (MQW) in which a strong
By using the anomalous Hall effect (AHE) and anomalous circular photogalvanic effect (ACPGE) which are all derived from reciprocal spin Hall effect (RSHE), we obtained the ratio between the spin diffusion coefficient and the mobility of spin-polarized carriers

Summary

Introduction

Much attention has been given to semiconductor spintronics for the promising applications in information technology [1, 2]. One of the fundamental issues on semiconductor spintronics is the spin transport and its manipulation, including spin-related diffusion and drift. The anomalous circular photogalvanic effect (ACPGE) [3,4,5] and anomalous Hall effect (AHE) [6,7,8,9,10], which are derived from the same spin-orbit coupling (SOC) mechanisms (intrinsic or extrinsic) based on the reciprocal spin Hall effect (RSHE), open avenues to the study of the relationship between the diffusion and the drift of photoinduced spin-polarized electrons. According to [11], the ratio of the diffusion coefficient to the mobility of the photoinduced spin-polarized electrons has been measured to Rashba SOC had been demonstrated in previous studies [10, 12, 13].

Methods

Results

Conclusion