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heterostructures: Examination of spin relaxation mechanism
摘要： The thickness, temperature, and composition studies of spin diffusion length (SDL) and spin Hall angle (SHA) are performed by measuring the spin Hall magnetoresistance in Pd1?xPtx/Y3Fe5O12 (=YIG) heterostructures. The SDL is found to be invariant to changes in the electron momentum relaxation time by varying the temperature, the normal metal (NM) thickness, or the alloy composition, while the SHA exhibits a nonmonotonic dependence on temperature. These findings suggest the appearance of D’yakonov-Perel’ spin relaxation mechanism and phonon skew scattering in our heterostructures that is associated with strong interfacial Rashba spin-orbit coupling (IRSOC). At last, we employ the ab initio calculations to quantify the IRSOC at the inversion-symmetry-broken NM/YIG interface.
关键词： spin diffusion length,spin relaxation mechanism,spin Hall angle,interfacial Rashba spin-orbit coupling,PdPt/YIG heterostructures
更新于2025-09-23 15:23:52
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Precision mapping the topological bands of 2D spin-orbit coupling with microwave spin-injection spectroscopy
摘要： To investigate the band structure is one of the key approaches to study the fundamental properties of a novel material. We report here the precision band mapping of a 2-dimensional (2D) spin-orbit (SO) coupling in an optical lattice. By applying the microwave spin-injection spectroscopy, the band structure and spin-polarization distribution are achieved simultaneously. The band topology is also addressed with observing the band gap close and re-open at the Dirac points. Furthermore, the lattice depth and the Raman coupling strength are precisely calibrated with relative errors in the order of 10?3. Our approach could also be applied for exploring the exotic topological phases with even higher dimensional system.
关键词： Topological band,Microwave spin-injection spectroscopy,Spin polarization,Topological phase transition,2D spin-orbit coupling
更新于2025-09-23 15:23:52
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Lateral interfaces of transition metal dichalcogenides: A stable tunable one-dimensional physics platform
摘要： We study in-plane lateral heterostructures of commensurate transition-metal dichalcogenides, such as MoS2-WS2 and MoSe2-WSe2, and find interfacial and edge states that are highly localized to these regions of the heterostructure. These are one-dimensional (1D) in nature, lying within the band gap of the bulk structure and exhibiting complex orbital and spin structure. We describe such heteroribbons with a three-orbital tight-binding model that uses first principles and experimental parameters as input, allowing us to model realistic systems. Analytical modeling for the 1D interfacial bands results in long-range hoppings due to the hybridization along the interface, with strong spin-orbit couplings. We further explore the Ruderman-Kittel-Kasuya-Yosida indirect interaction between magnetic impurities located at the interface. The unusual features of the interface states result in effective long-range exchange noncollinear interactions between impurities. These results suggest that transition-metal dichalcogenide interfaces could serve as stable, tunable 1D platform with unique properties for possible use in exploring Majorana fermions, plasma excitations, and spintronics applications.
关键词： spin-orbit coupling,interface states,transition metal dichalcogenides,RKKY interaction,tight-binding model,lateral heterostructures
更新于2025-09-23 15:23:52
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General condition for realizing a collinear spin-orbit effective magnetic field in two-dimensional electron systems and its application to zinc-blende and wurtzite quantum wells
摘要： In this paper, we have studied two-dimensional (2D) electron systems described by the effective Hamiltonians containing spin-orbit coupling (SOC) terms up to an arbitrary odd order in wave vector k. The general condition for realizing a SOC-induced effective magnetic field (SOF) in such systems, formulated only in terms of the SOC parameters, is derived. When this condition is satisfied, the projection of the electron spin on the direction of the collinear SOF is a conserved quantity. The complete set of the k-linear and k-cubic Dresselhaus SOC contributions to the effective 2D Hamiltonian of an arbitrarily oriented zinc-blende quantum well is computed by a proper averaging of the corresponding tight-binding bulk SOC Hamiltonian. We investigate possibilities for realization of the collinear SOF in zinc-blende quantum wells of different orientation and obtain some interesting findings, which supplement the results of earlier works. Application of the developed formalism to wurtzite semiconductor 2D systems shows that the collinear SOF can be also realized in a wide class of such quantum wells.
关键词： effective magnetic field,spin-orbit coupling,quantum wells,wurtzite,zinc-blende
更新于2025-09-23 15:23:52
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Two dimensional topological insulators in bilayer BiB
摘要： With the help of ?rst-principles calculations, we propose a new type of two dimensional (2D) topological insulator BiB with bilayer hexagonal lattice. Its dynamic stability was con?rmed by the phonon spectrum. When spin-orbit coupling (SOC) e?ect is not considered, the low energy electronic states around the Fermi level show metallic characteristics. However, the SOC will induce a global band gap and turn this 2D material into topological insulators with nontrivial edge states. Surprisingly, two mechanisms, including crystal ?eld and strong SOC, induce two band inversions and manipulate the low energy electronic states simultaneously. The BiB provides a fertile platform for studying the interactions between the two di?erent mechanisms in the same topological insulator. Moreover, the sizable global nontrivial band gap indicates its high working temperature.
关键词： Topological insulator,Edge states,Z2,Spin-orbit coupling (SOC)
更新于2025-09-23 15:22:29
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Resonant inelastic x-ray incarnation of Young’s double-slit experiment
摘要： Young’s archetypal double-slit experiment forms the basis for modern diffraction techniques: The elastic scattering of waves yields an interference pattern that captures the real-space structure. Here, we report on an inelastic incarnation of Young’s experiment and demonstrate that resonant inelastic x-ray scattering (RIXS) measures interference patterns, which reveal the symmetry and character of electronic excited states in the same way as elastic scattering does for the ground state. A prototypical example is provided by the quasi-molecular electronic structure of insulating Ba3CeIr2O9 with structural Ir dimers and strong spin-orbit coupling. The double “slits” in this resonant experiment are the highly localized core levels of the two Ir atoms within a dimer. The clear double-slit-type sinusoidal interference patterns that we observe allow us to characterize the electronic excitations, demonstrating the power of RIXS interferometry to unravel the electronic structure of solids containing, e.g., dimers, trimers, ladders, or other superstructures.
关键词： Resonant inelastic x-ray scattering,quasi-molecular orbitals,electronic excitations,Young's double-slit experiment,spin-orbit coupling,interference patterns
更新于2025-09-23 15:22:29
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Interference of bright solitons in harmonically trapped pseudo-spin polarization Bose-Einstein condensates
摘要： We study interference behaviors between spin-orbit-coupled Bose-Einstein condensates confined in a harmonic trap. By solving the coupled nonlinear Schr?dinger equations in the real-time domain, interference properties of the pseudo-spin condensates are carefully investigated in different parameter regimes. We map out the role of the spin-orbit coupling, the energy detuning and relative phases during the collisions. It is also found that the spin-orbit coupling controls the population transfer between the condensates. The presentation of spin-orbit coupling enriches the dynamical process of the bright soliton interference.
关键词： Spin-orbit coupling,Interference,Bright soliton,Spin polarization
更新于2025-09-23 15:21:21
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Controlling Topological States in Topological/Normal Insulator Heterostructures
摘要： We have performed a systematic investigation of the nature of the nontrivial interface states in topological/normal insulator (TI/NI) heterostructures. On the basis of first principles and a recently developed scheme to construct ab initio effective Hamiltonian matrices from density functional theory calculations, we studied systems of realistic sizes with high accuracy and control over the relevant parameters such as TI and NI band alignment, NI gap, and spin?orbit coupling strength. Our results for IV?VI compounds show the interface gap tunability by appropriately controlling the NI thickness, which can be explored for device design. Also, we verified the preservation of an in-plane spin texture in the interface-gaped topological states.
关键词： density functional theory,heterostructures,spin?orbit coupling,topological insulators,normal insulators
更新于2025-09-23 15:21:21
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Transmission-Line Model for Materials with Spin-Momentum Locking
摘要： We provide a transmission-line representation for channels exhibiting spin-momentum locking (SML) that can be used for both time-dependent and steady-state transport analysis on a wide variety of materials with spin-orbit coupling such as topological insulators, Kondo insulators, transition metals, semimetals, oxide interfaces, and narrow band-gap semiconductors. This model is based on a time-dependent four-component di?usion equation obtained from the Boltzmann transport equation assuming linear response and elastic scattering in the channel. We classify all electronic states in the channel into four groups (U+, D+, U?, and D?) depending on the spin index [up (U), down (D)] and the sign of the x component of the group velocity (+, ?) and assign an average electrochemical potential to each of the four groups to obtain the four-component di?usion equation. For normal metal channels, the model decouples into the well-known transmission-line model for charge and a time-dependent version of the Valet-Fert equation for spin. We ?rst show that, in the steady-state limit, our model leads to simple expressions for charge-spin interconversion in SML channels in good agreement with existing experimental data on diverse materials. We then use the full time-dependent model to study spin-charge separation in the presence of SML, a subject that has been controversial in the past. Our model shows that the charge and spin signals travel with two distinct velocities, resulting in well-known spin-charge separation, which is expected to persist even in the presence of SML. However, our model predicts that the lower velocity signal is purely spin, while the higher velocity signal is largely charge with an additional spin component proportional to the degree of SML, which has not been noted before. Finally, we note that our model can be used within standard circuit simulators such as SPICE to obtain numerical results for complex geometries.
关键词： spin-orbit coupling,spin-charge separation,transmission-line model,topological insulators,charge-spin interconversion,spin-momentum locking
更新于2025-09-23 15:21:01
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First-principles theory of giant Rashba-like spin splitting in bulk GeTe
摘要： Large Rashba-like spin splitting has been recently found in the band structure of certain bulk ferroelectrics. In contrast to the relativistic Rashba effect, the chiral spin texture and large spin splitting of the electronic bands depend strongly on the character of the band and atomic spin-orbit coupling. We establish that this can be traced back to an interplay between the orbital angular momentum and ferroelectricity. The additional dependence on the orbital composition of the bands is crucial to the complete picture of the effect. Results from ?rst-principles calculations on ferroelectic GeTe verify the key predictions of the model.
关键词： Rashba-like spin splitting,orbital angular momentum,ferroelectricity,spin-orbit coupling,GeTe
更新于2025-09-23 15:21:01