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Unconventional charge and spin-dependent transport properties of a graphene nanoribbon with line-disorder
摘要： Electronic transport with a line (or a few lines) of Anderson-type disorder in a zigzag graphene nanoribbon is investigated in the presence of Rashba spin-orbit interaction. Such line-disorders give rise to a peculiar behavior in both charge as well as spin-polarized transmission in the following sense. In the weak-disorder regime, the charge transport data show Anderson localization up to a certain disorder strength, beyond which the extended states emerge and start dominating over the localized states. These results are the hallmark signature of a selectively disordered (as opposed to bulk disorder) graphene nanoribbon. However, the spin-polarized transport shows a completely contradicting behavior. Further, the structural symmetries are shown to have an important role in the spintronic properties of the nanoribbons. Moreover, the edge-disorder scenario (disorder selectively placed at the edges) seems to hold promise for the spin-filter and switching device applications.
关键词： Anderson localization,spin transport,graphene nanoribbon,line-disorder,Rashba spin-orbit interaction
更新于2025-09-23 15:23:52
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Preparation of thulium iron garnet ceramics and investigation of spin transport properties in thin films
摘要： Compensated ferrimagnetic thulium iron garnet ceramics were prepared by the sol-gel method, which is significantly better than conventional solid-state reactions. Saturation magnetization yielded a maximum of 16.7 emu/g for specimens sintered at 900 °C. Subsequently, using the TmIG bulk as the target, an epitaxial film was grown by pulsed laser deposition. Furthermore, the spin transport properties of film with an attached 5 nm-thick platinum layer were studied in terms of longitudinal spin Seebeck effect (LSSE) and spin Hall magnetoresistance (SMR). The LSSE coefficient was as high as 0.38 μV/K and the SMR was 0.0072%. These results indicated that the bulk material and thin film presented excellent qualities, which are extremely important for the fundamental investigation of novel spin transport behaviour in compensated ferrimagnetic insulators. These results also provide more alternatives for spintronic materials.
关键词： Magnetic insulators,Thulium iron garnet,Spin transport properties,Compensated ferrimagnet
更新于2025-09-23 15:22:29
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Domain wall dynamics due to femtosecond laser-induced superdiffusive spin transport
摘要： Manipulation of magnetic domain walls via a helicity-independent laser pulse has recently been experimentally demonstrated and various physical mechanisms leading to domain wall dynamics have been discussed. Spin-dependent superdiffusive transport of hot electrons has been identified as one of the possible ways to affect a magnetic domain wall. Here, we develop a model based on superdiffusive spin-dependent transport to study the laser-induced transport of hot electrons through a smooth magnetic domain wall. We show that the spin transfer between neighboring domains can enhance ultrafast demagnetization in the domain wall. More importantly, our calculations reveal that when the laser pulse is properly focused onto the vicinity of the domain wall, it can excite sufficiently strong spin currents to generate a spin-transfer torque that can rapidly move the magnetic domain wall by several nanometers in several hundred femtoseconds, leading to a huge nonequilibrium domain wall velocity.
关键词： spin-transfer torque,ultrafast demagnetization,magnetic domain walls,superdiffusive spin transport,laser-induced dynamics
更新于2025-09-23 15:21:01
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Spin-conserved electron transport to InGaAs quantum dots through GaAs/AlGaAs superlattice
摘要： We report on the spin-conserved electron transport to self-assembled InGaAs quantum dots (QDs) through GaAs/AlGaAs superlattice (SL) by circularly polarized time-resolved photoluminescence spectroscopy of the QD excited states with the selective excitation for the SL minibands. The spin transport properties largely depend on the AlGaAs barrier thickness of the SL. The SL with a thinner barrier demonstrates a quantum spin transport to QDs with highly conserving the electron-spin polarization during the transport process through the SL minibands.
关键词： spin transport,superlattice,semiconductor quantum dot,spin dynamics
更新于2025-09-19 17:13:59
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High-performance spin rectification in gallium nitride-based molecular junctions with asymmetric edge passivation
摘要： The spin transport properties of molecular devices constructed from zigzag gallium nitride nanoribbons (ZGaNNRs) are investigated by applying the non-equilibrium Green’s function formalism in combination with density functional theory. The computational results indicate that ZGaNNR systems show spin rectification with a high efficiency, approaching nearly 109, giant magnetoresistance with a ratio up to 108, perfect spin-filtering, and negative differential resistance effects. Importantly, our results reveal that intrinsic rectification can be observed regardless of their width. The microscopic origins of the rectification are revealed and discussed in terms of a spin-resolved transmission spectrum, the band structures of the ZGaNNRs, and the molecular projected self-consistent Hamiltonian. Our findings could be useful for designing GaN-based spintronic nanodevices.
关键词： spin transport,molecular junctions,asymmetric edge passivation,gallium nitride,spintronic devices
更新于2025-09-09 09:28:46