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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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True spin and pseudo spin entanglement around Dirac Points in graphene with Rashba spin–orbit interaction
摘要： We analytically obtained the Schmidt decomposition of the entangled state between the pseudo spin and the true spin in graphene with Rashba spin–orbit coupling. The entangled state has the standard form of the Bell state, where the SU(2) spin symmetry is broken. These states can be explicitly expressed as the superposition of two nonorthogonal, but mirror symmetrical spin states entangled with the pseudo spin states. Because of the closely locking between the pseudo spin and the true spin, it is found that the orbit curve in the spin-polarization parameter space for the fixed equi-energy contour around Dirac points has the same shape as the δk-contour. Due to the spin–orbit coupling that cause the topological transition in the local geometry of the dispersion relation, the new equi-energy contours around the new emergent Dirac Points can be obtained by squeezing the one around the original Dirac point. The spin texture in the momentum space around the Dirac points is analyzed under the Rashba spin–orbit interaction and it is found that the orientation of the spin polarization at each crystal momentum k is independent of the Rashba coupling strength.
关键词： Spin texture,Entangled spin states,Rashba spin–orbit interaction
更新于2025-09-23 15:21:21
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Influences of Rashba Spin-Orbit Coupling on First Excited State of Magnetopolaron in Parobolic Quantum Dot
摘要： The properties of the first excited state of a magnetopolaron in a patabolic quantum dot (PQD) are studied with the Lee-Low-Pines unitary transformation (LLPUT) and variational method of Pekar-type (VMPT). We find that the external magnetic field and the motion of the electron can trigger the Rashba effect in the first excited state and they play a virtual role in determining properties of the magnetopolaron in the parabolic PQD system. Furthermore, our results indicate the Rashba spin-orbit coupling(RSOC), confined potential, electron-phonon coupling, magnetic field and phonon wave vector promote a variation of the first excited state energy (FESE). In addition, the rule that the first excited state energy changes with one of four factors is not affected by the RSOC.
关键词： First excited state energy,Magnetopolaron,Rashba spin-orbit interaction,Quantum dot
更新于2025-09-23 15:19:57
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Nonlocal spin-charge conversion via Rashba spin-orbit interaction
摘要： We show theoretically that conversion between spin and charge by spin-orbit interaction in metals occurs even in a nonlocal setup where magnetization and spin-orbit interaction are spatially separated if electron diffusion is taken into account. Calculation is carried out for the Rashba spin-orbit interaction treating the coupling with a ferromagnet perturbatively. The results indicate the validity of the concept of effective spin gauge field (spin motive force) in the nonlocal configuration. The inverse Rashba-Edelstein effect observed for a trilayer of a ferromagnet, a normal metal and a heavy metal can be explained in terms of the nonlocal effective spin gauge field.
关键词： nonlocal setup,effective spin gauge field,spin-charge conversion,Rashba spin-orbit interaction,electron diffusion,inverse Rashba-Edelstein effect
更新于2025-09-19 17:15:36
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Impact of a topological defect and Rashba spin-orbit interaction on the thermo-magnetic and optical properties of a 2D semiconductor quantum dot with Gaussian confinement
摘要： In this paper, we examine the effect of introducing a conical disclination on the thermal and optical properties of a two dimensional GaAs quantum dot in the presence of a uniform and constant magnetic field. In particular, our model consists of a single-electron subject to a confining Gaussian potential with a spin-orbit interaction in the Rashba approach. We compute the specific heat and the magnetic susceptibility from the exact solution of the Schr?dinger equation via the canonical partition function, and it is shown that the peak structure of the Schottky anomaly is linearly displaced as a function of the topological defect. We found that such defect and the Rashba coupling modify the values of the temperature and magnetic field in which the system behaves as a paramagnetic material. Remarkably, the introduction of a conical disclination in the quantum dot relaxes the selection rules for the electronic transitions when an external electromagnetic field is applied. This creates a new set of allowed transitions causing the emergence of semi-suppressed resonances in the absorption coefficient as well as in the refractive index changes which are blue-shifted with respect to the regular transitions for a quantum dot without the defect.
关键词： Rashba spin-orbit interaction,optical properties,thermo-magnetic properties,topological defect,2D semiconductor quantum dot,Gaussian confinement
更新于2025-09-11 14:15:04