Narrow Results

We start by investigating the arising of a spin-orbit coupling and a Darwin-type term that stem from Lorentz symmetry breaking effects in the CPT-odd sector of the Standard Model Extension. Then, we establish a possible scenario of the violation of the Lorentz symmetry that gives rise to a linear confining potential and an effective electric field in which determines the spin-orbit coupling for a neutral particle analogous to the Rashba coupling [E. I. Rashba, Sov. Phys. Solid State2, 1109 (1960)]. Finally, we confine the neutral particle to a quantum dot [W.-C. Tan and J. C. Inkson, Semicond. Sci. Technol.11, 1635 (1996)] and analyze the influence of the linear confining potential and the spin-orbit coupling on the spectrum of energy.

The uniaxially strained graphene monolayer on transition metal dichalcogenide (GrTMD) substrate, constituting a van der Waals heterostructure (vdWH), is found to possess unusual intra-band plasmon dispersion ($\omega \sim q^{2/3}$) with stronger incarceration compared to that of a standalone, doped graphene for finite doping in the long wavelength limit. The intra-band absorbance of GrTMD is found to be an increasing (decreasing) function of the strain field (frequency) at a given frequency (strain field). It is also observed that whereas the strain field is responsible for the valley polarization, a Rashba coupling-dependent pseudo Zeeman term arising due to the interplay of substrate-induced interactions is found to bring about the spin degeneracy lifting and the gate voltage tunable spin polarization. The latter turns out to be inversely proportional to the square root of the carrier concentration.

In this paper, the anisotropic magnetoresistance (AMR) and electron conductivity of electron gas in presence of the Rashba and Dresselhaus spin-orbit coupling are investigated. Boltzmann equation is solved exactly for low temperature, including electron scattering. Calculations have been performed within the coherent potential approximation. Results of the transport study demonstrate that the AMR enhances as the Rashba strength increases. It is also observed that the AMR depends critically on spin-orbit coupling strength, wave vector and Dresselhaus strength.

The spin-sensitive charge oscillation, controlled by an external magnetic field, was recently proposed as a mechanism of transformations of qubits, defined as two-electron spin-charge Wannier molecules in a square quantum dot.¹ The paper expands this idea by including the effects of Rashba-type spin-orbit coupling. The problem is studied theoretically by mapping the system to an analytic effective Hamiltonian for 8 low-energy states, comprising singlet and triplet on each dot diagonal. The validity of mapping is confirmed by comparing the energy and spin of full and mapped system, and also by the reproduction of charge-oscillation dynamics in the presence of magnetic flux. The newly introduced Rashba coupling significantly enriches the system dynamics, affecting the magnitude of charge oscillations and allowing the controlled transitions between singlet and triplet states due to the spin rotations, induced by spin-orbit coupling. The results indicate the possibility for use of the studied system for quantum information processing, while possible extensions of the system to serve as a qubit in a universal quantum computer, fulfilling all five Di Vincenzo criteria, is also discussed.