在对称量子点（QD）中，众所周知，自旋热点（即，尖点状结构，由于在能级或反交叉点附近存在简并性）对于纯Rashba情况存在，但对于纯Dresselhaus情况不存在[Phys.Rev.Lett. 95，076805（2005）]。由于Dresselhaus自旋轨道耦合在GaAs和GaSb量子点中占主导地位，因此即使对于纯Dresselhaus情况，也必须找到自旋热点或尖点结构的确切位置。在本文中，第一次，我们提出的分析和数值计算结果表明，自旋热点也可以看到纯Dresselhaus自旋轨道耦合的情况下，通过外部栅极诱导大的各向异性。在自旋热点处或附近，自旋跃迁速率提高，退相干时间比没有自旋热点的情况减少了几个数量级。因此，当设计用于量子逻辑门、固态量子计算和量子信息处理中的可能实现的基于QD自旋的晶体管时，应当避免这样的位置。也可以提取精确的实验数据（Phys. Rev. Lett. 100，046803（2008））从我们开发的理论模型中获得声子介导的自旋翻转速率。
英文摘要：
In symmetric quantum dots (QDs), it is well known that the spin-hot spot (i.e., the cusp-like structure due to the presence of degeneracy near the level or anticrossing point) is present for the pure Rashba case but is absent for the pure Dresselhaus case [Phys. Rev. Lett. 95, 076805 (2005)]. Since the Dresselhaus spin-orbit coupling dominates over the Rashba spin-orbit coupling in GaAs and GaSb QDs, it is important to find the exact location of the spin-hot spot or the cusp-like structure even for the pure Dresselhaus case. In this paper, for the first time, we present analytical and numerical results that show that the spin-hot spot can also be seen for the pure Dresselhaus spin-orbit coupling case by inducing large anisotropy through external gates. At or nearby the spin-hot spot, the spin transition rate enhances and the decoherence time reduces by several orders of magnitude compared to the case with no spin-hot spot. Thus one should avoid such locations when designing QD spin based transistors for the possible implementation in quantum logic gates, solid state quantum computing and quantum information processing. It is also possible to extract the exact experimental data (Phys. Rev. Lett. 100, 046803 (2008)) for the phonon mediated spin-flip rates from our developed theoretical model.
We address the electromagnetic properties of two-dimensional electron gas confined by a dielectric environment in the presence of both Rashba and Dresselhaus spin-orbit interactions. It is demonstrated that off-diagonal components of the conductivity tensor resulting from a delicate interplay between Rashba and Dresselhaus couplings lead to the hybridization of transverse electric and transverse magnetic surface electromagnetic modes localized at the interface. We show that the characteristics of these hybrid surface waves can be controlled by additional intense external off-resonant coherent …
The Rashba and Dresselhaus types of spin-orbit coupling are two typical linear coupling forms. We establish the fundamental physics of a model which can be viewed as the double version of the Rashba and Dresselhaus spin-orbit coupling. This model describes the low energy physics of a class of massless Dirac fermions in spin-orbit systems. The physical properties of the massless Dirac fermions are determined by the mathematical relations of spin-orbit coefficients. For equal Rashba and Dresselhauss coupling constants, k-independent eigenspinors and a persistent spin helix combined with massless…
New exact and asymptotical results for the one particle Green's function of 2D electrons with combined Rashba - Dresselhaus spin - orbit interaction in the presence of in-plane uniform magnetic field are presented. A special case that allows an exact analytical solution is also highlighted. To demonstrate the advantages of our approach we apply the obtained Green's function to calculation of electron density and magnetization
Anisotropic universal conductance fluctuations in disordered quantum wires with Rashba and Dresselhaus spin-orbit interaction and applied in-plane magnetic field
Rashba and linear Dresselhaus interactions are believed to yield dominant contribution to the spin splitting of two-dimensional electrons in the quantum wells based on A$_3$B$_5$ compounds. We show that the interfacial spin-orbit interaction significantly renormalizes the value of the corresponding Rashba ($α_{SIA}$) and Dresselhaus ($α_{BIA}$) parameters. For this purpose, we solve the effective mass equation in a quantum well supplemented by the original boundary conditions on the atomically sharp interfaces and calculate the interfacial contributions to $α_{SIA}$ and $α_{BIA}$. Our results …
We theoretically investigate the spin-dependent Seebeck effect in an Aharonov-Bohm mesoscopic ring in the presence of both Rashba and Dresselhaus spin-orbit interactions under magnetic flux perpendicular to the ring. We apply the Green's function method to calculate the spin Seebeck coefficient employing the tight-binding Hamiltonian. It is found that the spin Seebeck coefficient is proportional to the slope of the energy-dependent transmission coefficients. We study the strong dependence of spin Seebeck coefficient on the Fermi energy, magnetic flux, strength of spin-orbit coupling, and tempe…
The spin splitting of conduction band electrons in inversion-asymmetric InGaAs/InP quantum wells is studied by Shubnikov-de Haas measurements combining the analysis of beating patterns and coincidence measurements in doubly tilted magnetic fields. The method allows us to determine the absolute values of the Rashba and linear Dresselhaus spin-orbit interaction coefficients, their relative sign and the full Landé g-tensor. This is achieved by analyzing the anisotropy of the beat node positions with respect to both polar and azimuthal angles between the magnetic field direction and the quantum we…
We theoretically consider spin pumping in a junction between a ferromagnetic insulator (FI) and a two-dimensional electron gas (2DEG) in which the Rashba and Dresselhaus spin-orbit interactions coexist. Using second-order perturbation theory, we derive an increase in linewidth in the case of an interfacial exchange coupling in a ferromagnetic resonance (FMR) experiment. We clarify how the enhancement of Gilbert damping depends on the resonant frequency and spin orientation of the FI. We show that this setup of an FMR experiment can provide information on the spin texture of 2DEG at the Fermi s…
Robustness of spin filtering against current leakage in a Rashba-Dresselhaus-Aharonov-Bohm interferometer
在早期的一篇论文[Phys. Rev. B 84，035323（2011）]中，我们提出了一种基于类金刚石干涉仪的自旋滤波器，该干涉仪同时受到Aharonov-Bohm通量和（Rashba和Dresselhaus）自旋轨道相互作用的影响。在这里，我们表明，出射电子自旋的全极化保持不变，即使当一个允许泄漏的电子从分支的干涉仪。一旦调谐其中一个分支上的栅极电压以实现它们之间的有效对称，则可以通过确定自旋-轨道相互作用强度和Aharonov-Bohm通量的电场和/或磁场来控制该极化。
A nonperturbative interaction of an electronic system with a laser field can substantially modify its physical properties. In particular, in two-dimensional (2D) materials with a lack of inversion symmetry, the achievement of a regime of strong light-matter coupling allows direct optical tuning of the strength of the Rashba spin-orbit interaction (SOI). Capitalizing on these results, we build a theory of the dynamical conductivity of a 2D electron gas with both Rashba and Dresselhaus SOIs coupled to an off-resonant high-frequency electromagnetic wave. We argue that strong light-matter coupling…
Spin-orbit interaction in semiconductor structures with broken space inversion symmetry leads to spin splitting of electron and hole states even in the absence of magnetic field. We discover that, beyond the Rashba and Dresselhaus contributions, there is an additional type of the zero-field spin splitting which is caused by the interplay of the cubic shape of crystal unit cell and macroscopic structure asymmetry. In quantum wells grown along low-symmetry crystallographic axes, this type of spin-orbit interaction couples the out-of-plane component of carrier's spin with the in-plane momentum wh…
The Rashba-Dresselhaus effect is the splitting of doubly degenerate band extrema in semiconductors, accompanied by the emergence of counter-rotating spin textures and spin-momentum locking. Here we investigate how this effect is modified by lattice vibrations. We show that, in centrosymmetric non-magnetic crystals, for which a bulk Rashba-Dresselhaus effect is symmetry-forbidden, electron-phonon interactions can induce a phonon-assisted, dynamic Rashba-Dresselhaus spin splitting in the presence of an out-of-equilibrium phonon population. In particular, we show how Rashba, Dresselhaus, or Weyl …
In the presence of Rashba-Dresselhaus coupling, strong spin-orbit interactions in liquid crystal optical cavities result in a distinctive spin-split entangled dispersion. Spin coherence between such modes give rise to an optical persistent-spin-helix. In this letter, we introduce optical gain in such a system, by dispersing a molecular dye in a liquid-crystal microcavity. We demonstrate both lasing in the Rashba-Dresselhaus regime and the emergence of an optical persistent spin helix.
We investigate the properties of persistent charge current driven by magnetic flux in a quasi-periodic mesoscopic Fibonacci ring with Rashba and Dresselhaus spin-orbit interactions. Within a tight-binding framework we work out individual state currents together with net current based on second-quantized approach. A significant enhancement of current is observed in presence of spin-orbit coupling and sometimes it becomes orders of magnitude higher compared to the spin-orbit interaction free Fibonacci ring. We also establish a scaling relation of persistent current with ring size, associated wit…
We solve analytically the energy eigenvalue problem of narrow semiconductor quantum rings with a general spin-orbit term that includes as a special case the Rashba and Dresselhaus interactions acting simultaneously. The eigenstates and eigenenergies of the system are found for arbitrary values of the spin-orbit coupling constants without making use of approximations. The general eigenstates are expressed as products of a scalar Mathieu function and a spinor factor which is periodic or pseudo-periodic on the ring. Our general solution reduces to the previously found solutions for particular com…
A major impediment towards realizing technologies based on the emerging principles of antiferromagnetic spintronics is the shortage of suitable materials. In this paper, we propose a design of polar|nonpolar heterostructures of perovskite oxides, where a single unit cell of SrIrO3 is sandwiched between a thin film of LaAlO3 and a substrate of SrTiO3. Our calculations within the framework of density-functional theory + Hubbard U + spin-orbit coupling reveal a two-dimensional conducting layer with electron and hole pockets at the interface, exhibiting a strong anisotropic Rashba-Dresselhaus effe…
Spin orbit interaction (SOI) having a complicated energy spectrum with a conical point and four critical points are promising candidates to observe electron topological transitions. In the present paper we have investigated the evolution of the electron spectrum and isoenergetic contours under the influence of parallel magnetic field. General formulas for energies of critical points for arbitrary values of SOI constants and magnetic field are found. The existence of critical magnetic fields at which a number of critical points is changed has been predicted. The magnetic field driving topologic…
We derive a closed-form expression for the weak localization (WL) corrections to the magnetoconductivity of a 2D electron system with arbitrary Rashba $α$ and Dresselhaus $β$ (linear) and $β_3$ (cubic) spin-orbit interaction couplings, in a perpendicular magnetic field geometry. In a system of reference with an in-plane $\hat{z}$ axis chosen as the high spin-symmetry direction at $α= β$, we formulate a new algorithm to calculate the three independent contributions that lead to WL. The antilocalization is counterbalanced by the term associated with the spin-relaxation along $\hat{z}$, dependent…
Persistent, oscillatory charge and spin currents are shown to be driven by a two-component terahertz laser pulse in a one-dimensional mesoscopic ring with Rashba-Dresselhaus spin orbit interactions (SOI) linear in the electron momentum. The characteristic interference effects result from the opposite precession directions imposed on the electron spin by the two SOI couplings. The time dependence of the currents is obtained by solving numerically the equation of motion for the density operator, which is later employed in calculating statistical averages of quantum operators on few electron eige…
