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

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.

Carbon Nanodots in Photodynamic Antimicrobial Therapy: A Review

“…This technology remains to be further refined and tuned, with a vast array of metal substrates available to optimize the enhanced absorption rather than emission coupling mechanism for carbon dots in ME-ROS systems; however, these results do in fact reveal an additional way that carbon dots may be employed in APDT hybrid systems. This application of a carbon dot/silver nanoparticle hybrid is particularly intriguing, as typically these capitalize primarily on the inherent antibiotic character of the silver particles [ 81 , 82 ], employing carbon dots instead as either imaging agents [ 83 ] or as reducing agents in the initial silver particle synthesis [ 84 , 85 , 86 , 87 , 88 ].…”

A rational design of multimodal asymmetric nanoshells as efficient tunable absorbers within the biological optical window

“…As one can see, two distinct plasmon resonance peaks can be observed in the spectra of CS, PS and OS; while the spectrum of NE exhibits three LSPR peaks.To understand this plasmonic behavior, the plasmon hybridization of solid and cavity plasmon modes can be applied to this geometry. According to the hybridization model, metallic nanoshell supports plasmon modes at the inner and outer surfaces of the shell which can interact with each other due to the finite thickness of the shell 46 – 48 . This interaction results in the splitting of the plasmon resonances into two hybridized resonances; the lower energy bonding mode (BM) and the higher energy antibonding mode (ABM).…”

Current-Induced Spin Photocurrent in GaAs at Room Temperature

“…The use of circularly polarized light for spin injection and regulation has been widely studied in many materials. The resulting effects of the circularly photogalvanic effect (CPGE), anomalous circularly photogalvanic effect (ACPGE), and photo-induced anomalous Hall effect (PAHE), etc., are widely reflected in various semiconductors and topological materials [ 14 , 15 , 16 , 17 , 18 ]. CPGE is traditionally gyrotropic optical media with strong spin-orbit coupling.…”

“…As a consequence, the effect is ordinarily under the control of angular momentum selection rules of excitation with circularly polarized light [ 19 ]. ACPGE and PAHE are derived from the inverse spin Hall effect of spin-polarized photo-generated carrier diffusion and the drift under an electric field, respectively [ 16 ]. The circularly polarized photocurrent in the above effect, varying linearly with the applied bias voltage, can be self-driven without the external bias voltage [ 20 , 21 , 22 ], whereas the relationship between the circularly polarized photocurrent and the applied bias voltage stemming from the CISP is nonlinear.…”