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oe1(光电查) - 科学论文

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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

  • [IEEE 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Kiev (2018.4.24-2018.4.26)] 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Influence of Spin-Orbit Interaction on the Magneto-Optical Spectra of InSb Quantum Rings

    摘要： The theoretical calculations of dependences of energy levels and absorption spectra of electrons in the quantum ring by a quasi-parabolic shape on the applied external magnetic field were carried out. The influence of spin-orbit interaction was taken into account in these calculations. Spin-orbit interaction leads to appearance of change in the dependence of absorption frequency of quantum rings on applied magnetic field.

    关键词： spin-orbit interaction,absorption spectrum,quantum ring

    更新于2025-09-23 15:22:29

  • Spin-orbit interaction of Tm3+ - ground level and crystal field strength

    摘要： The ground level 3H6 of Tm3+ ions in a number of crystals has been examined through the matrix elements of spin – orbit interaction. The latter have been determined comparable with the separation between 3H6 and the first excited level 3F4. The normalized ratios of spin – orbit interactions relative to the free ion value of Tm IV as a function of the scalar crystal field parameter Nv have been found to vary analogous to the nephelauxetic effect. The relationships between maximum splitting of 3H6, spin-orbit coupling constant, crystal-field parameters and the Nv have been also studied for the presented 42 stoichiometric or doped crystals containing Tm3+. The compounds include halogenides, organic complexes, oxides, oxohalides, and semiconductors.

    关键词： Thulium (3+),Crystal field strength,Spin-orbit interaction,Ground level

    更新于2025-09-23 15:22:29

  • 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

  • Vectorial control of the spin-orbit interaction in suspended InAs nanowires

    摘要： Semiconductor nanowires featuring strong spin-orbit interactions (SOI), represent a promising platform for a broad range of novel technologies, such as spintronic applications or topological quantum computation. However, experimental studies into the nature and the orientation of the SOI vector in these wires remain limited despite being of upmost importance. Typical devices feature the nanowires placed on top of a substrate which modifies the SOI vector and spoils the intrinsic symmetries of the system. In this work, we report experimental results on suspended InAs nanowires, in which the wire symmetries are fully preserved and clearly visible in transport measurements. Using a vectorial magnet, the non-trivial evolution of weak anti-localization (WAL) is tracked through all 3D space, and both the spin-orbit length lSO and coherence length l? are determined as a function of the magnetic field magnitude and direction. Studying the angular maps of the WAL signal, we demonstrate that the average SOI within the nanowire is isotropic and that our findings are consistent with a semiclassical quasi-1D model of WAL adapted to include the geometrical constraints of the nanostructure. Moreover, by acting on properly designed side gates, we apply an external electric field introducing an additional vectorial Rashba spin-orbit component whose strength can be controlled by external means. These results give important hints on the intrinsic nature of suspended nanowire and can be interesting for the field of spintronics as well as for the manipulation of Majorana bound states in devices based on hybrid semiconductors.

    关键词： weak anti-localization,spin-orbit interaction,Rashba effect,indium arsenide,nanowire

    更新于2025-09-23 15:21:01

  • Tunable topological charge vortex microlaser

    摘要： The orbital angular momentum (OAM) intrinsically carried by vortex light beams holds a promise for multidimensional high-capacity data multiplexing, meeting the ever-increasing demands for information. Development of a dynamically tunable OAM light source is a critical step in the realization of OAM modulation and multiplexing. By harnessing the properties of total momentum conservation, spin-orbit interaction, and optical non-Hermitian symmetry breaking, we demonstrate an OAM-tunable vortex microlaser, providing chiral light states of variable topological charges at a single telecommunication wavelength. The scheme of the non–Hermitian-controlled chiral light emission at room temperature can be further scaled up for simultaneous multivortex emissions in a flexible manner. Our work provides a route for the development of the next generation of multidimensional OAM-spin-wavelength division multiplexing technology.

    关键词： data multiplexing,orbital angular momentum,chiral light emission,non-Hermitian symmetry breaking,vortex light beams,spin-orbit interaction,microlaser,telecommunication wavelength

    更新于2025-09-23 15:21:01

  • Hole spin in tunable Ge hut wire double quantum dot

    摘要： Holes in germanium (Ge) exhibit strong spin-orbit interaction, which can be exploited for fast and all-electrical manipulation of spin states. Here, we report transport experiments in a tunable Ge hut wire hole double quantum dot. We observe the signatures of Pauli spin blockade (PSB) with a large singlet-triplet energy splitting of ~1.1 meV and extract the g factor. By analyzing the the PSB leakage current, we obtain a spin-orbit length ?????? of ~ 40–100 nm. Furthermore, we demonstrate the electric dipole spin resonance. These results lay a solid foundation for implementing high quality tunable hole spin-orbit qubits.

    关键词： Pauli spin blockade,electric dipole spin resonance,germanium,spin-orbit interaction,quantum dots

    更新于2025-09-23 15:19:57

  • Simultaneous effects of pressure, temperature, impurity location, SOI and magnetic field on THG of a pyramid quantum dot

    摘要： We have investigated simultaneous effects of pressure, temperature, impurity location, Rashba and Dresselhaus spin–orbit interaction and magnetic field on THG of realized GaAs/Al0.5Ga0.5As pyramid quantum dot with considering the wet layer. For this purpose, we have calculated the energy levels and wave function of one electron that is confined in constant potential, in presence of impurity, magnetic field, Rashba and Dresselhous SOI in various temperatures, pressure and impurity location in effective mass approximation by FEM. In the following, we have presented the effect of magnetic field, Rashba and Dresselhous SOI, temperature, pressure and impurity location on THG in various conditions. Results show that: (1) THG increases by increasing the magnetic field and the distance between the peaks decrease. Also, the peak corresponding to the E21 transition has a blue shift and the peaks corresponding to the E31/2 and E41/3 transitions have a red shift. (2) THG decreases and shifts to higher energies and has a small blue shift by augment of temperature. (3) THG enhances and all of peaks have a red shift by increment of pressure. (4) THG has a minimum around z0 = 4 nm in all magnetic field, temperature and pressure cases. Also, all of peaks have a blue shift by augment of z0 until z0 = 4 nm and then have a red shit by increasing the z0.

    关键词： Pyramid quantum dot,Spin orbit interaction,Third harmonic generation

    更新于2025-09-23 15:19:57

  • Superadiabatic spin-preserving control of a single-spin qubit in a double quantum dot with spin-orbit interaction

    摘要： A protocol for controlling the localization of an electron with a fixed projection of spin between two quantum dots in a material with spin-orbit (SO) interaction is studied. Due to SO coupling, the manipulation of the electron shuttling between both quantum dots also leads to a mixing between spin projections near to the avoided crossing of levels. We use a transitionless quantum driving approach, with neglect of SO interaction, to analytically design simple electric and magnetic pulses able to rapidly drive the electron along an adiabatic Landau-Zener manifold. We show that the same fields in the presence of SO can also give a fast high-fidelity transition between the qubit states. The performance of the proposed protocol is assessed in the presence of SO interactions of typical semiconductor materials.

    关键词： quantum dots,spin-orbit interaction,transitionless quantum driving,Landau-Zener process,qubit control

    更新于2025-09-23 15:19:57

  • 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