科研之友
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摘要
Nanothick semiconductors can grow orderly along a desired direction with the help of modern materialsgrowth technology such as molecular beam epitaxy, which allows researchers to fabricate the so-called layeredsemiconductor nanostructure (LSN) experimentally. Owing to the structure inversion symmetry broken by thelayered form in the LSN, the electron spins interact tightly with its momentums, in the literature referred to asthe spin-orbit coupling (SOC) effect, which can be modulated well by the interfacial confining electric field orthe stain engineering. These significant SOC effects can effectively eliminate the spin degeneracy of the electronsin semiconductor materials, induce the spin splitting phenomenon at the zero magnetic field and generate theelectron-spin polarization in the semiconductors. In recent years, the spin-polarized transport for electrons in theLSN has attracted a lot of research interests, which is because of itself scientific importance and potentialserving as spin polarized sources in the research field of semiconductor spintronics. Adopting the theoreticalanalysis combined with the numerical calculation, we investigate the spin-polarized transport induced by theRashba-type SOC effect for electrons in a single-layered semiconductor nanostructure (SLSN)-InSb. The presentresearch is to explore the new way of generating and manipulating spin current in semiconductor materialswithout any magnetic field, and focuses on developing new electron-spin filter for semiconductor spintronicsdevice applications. The improved transfer matrix method (ITMM) is exploited to exactly solve Schrodingerequation for an electron in the SLSN-InSb device, which allows us to calculate the spin-dependent transmissioncoefficient and the spin polarization ratio. Owing to a strong Rashba-type SOC, a considerable electron-spinpolarization effect appears in the SLSN-InSb device. Because of the effective potential experienced by theelectrons in the SLSN-InSb device, the spin polarization ratio is associated with the electron energy and the in-plane wave vector. In particular, the spin polarization ratio can be manipulated effectively by an externally-applied electric field or the semiconductor-layer thickness, owing to the dependence of the effective potential feltby the electrons in the SLSN-InSb device on the electric field or the layer thickness. Therefore, such an SLSN-InSb device can be used as a controllable electron-spin filter acting as a manipulable spin-polarized source forthe research area of semiconductor spintronics.
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单位桂林理工大学
