Longitudinal conductivity in ABC-stacked trilayer graphene under irradiating of linearly polarized light

We study the effect of linearly polarized light on the band structure and longitudinal conductivity in ABC-stacked trilayer graphene. The linearly polarized light can induce a pair of additional points in ABC-stacked trilayer graphene, where conduct and valence bands touch. The locations of these points are determined by the amplitude of the light. Furthermore, the layer pseudospin polarization can be controlled by the light. When the Fermi energy locates at Dirac points, i.e., E_f=0, the longitudinal conductivity shows resonance phenomena when the light is present. Away from the Dirac points, the longitudinal conductivity is unchanged as varying E_f for weak light field at larger Fermi energy, and the amplitude of longitudinal conductivity can be controlled by tuning the light field amplitude. Moreover, the effect of linearly polarized light on resonance phenomena in k-cubic Rashba-Dresselhaus system under the irradiating of linearly polarized light is discussed.     

Nonlinear photoncurrent in transition metal dichalcogenide with warping term under illuminating of light

We investigate the photoconductivities of injection current and the shift current in transition metal dichalcogenide with warping term in the presence of sublattice potential and spin orbit coupling.The system shows the valley photoconductivities of injection current and the photoconductivities of shift current.It is found that the warping term and the geometric tensor play a critical role in the system,which are responsible for the photoconductivities.Due to the interplay between the sublattice potential and the spin orbit coupling,the photoconductivities can be tuned.Furthermore,the effect of warping term on geometric tensor and the amplitude of the photoconductivities are also discussed.     

Spin Hall and spin Nernst effects in graphene with intrinsic and Rashba spin-orbit interactions

The spin Hall and spin Nernst effects in graphene are studied based on Green’s function formalism.We calculate intrinsic contributions to spin Hall and spin Nernst conductivities in the Kane-Mele model with various structures.When both intrinsic and Rashba spin-orbit interactions are present,their interplay leads to some characteristics of the dependence of spin Hall and spin Nernst conductivities on the Fermi level.When the Rashba spin-orbit interaction is smaller than intrinsic spin-orbit coupling,a weak kink in the conductance appears.The kink disappears and a divergence appears when the Rashba spin-orbit interaction enhances.When the Rashba spin-orbit interaction approaches and is stronger than intrinsic spin-orbit coupling,the divergence becomes more obvious.     

Current-induced pseudospin polarization in silicene

The pseudospin polarization induced by an external electric field in silicene in the presence of weakly spinindependent impurities is considered theoretically in the linear response regime based on Green’s function method. We study the effects of the interplay between the sublattice potential and the intrinsic spin orbit coupling on the pseudospin polarization. We show that the pseudospin polarization perpendicular to the electric field is independent of the impurity parameter, while the pseudospin polarization in the direction of the electric field is sensitive to the impurity parameter. The dependences of the pseudospin polarizations on the chemical potential are studied.     

Optical conductivity of ABA-stacked trilayer graphene

The optical conductivity of a trilayer graphene is studied using the Kubo-Greenwood formula. We calculate the real part of the diagonal optical conductivity of an ABA-stacked trilayer graphene with different Fermi energies. The optical conductivity arises from interband matrix elements of the electric current operator involving the transitions from the occupied states to the unoccupied ones. We study the dependence of the real part of the diagonal optical conductivity on the photon energy, and the role of the transitions.     

Transport properties of the topological Kondo insulator SmB_6 under the irradiation of light

In this paper, we study transport properties of the  point in the Brillouin zone of the topological Kondo insulator SmB_6 under the application of a circularly polarized light. The transport properties at high-frequency regime and lowfrequency regime as a function of the ratio(κ) of the Dresselhaus-like and Rashba-like spin–orbit parameter are studied based on the Floquet theory and Boltzmann equation respectively. The sign of Hall conductivity at high-frequency regime can be reversed by the ratio κ and the amplitude of the light. The amplitude of the current can be enhanced by the ratio κ.Our findings provide a way to control the transport properties of the Dirac materials at low-frequency regime.