Optical properties of a semi-Dirac material

Abstract

Within a Kubo formalism, we calculate the absorptive part of the dynamic longitudinal conductivity $\sigma (\Omega )$ of a 2D semi-Dirac material. In the clean limit, we provide separate analytic formulas for intraband (Drude) and interband contributions for $\sigma (\Omega )$ in both the relativistic and nonrelativistic directions. At finite doping, in the relativistic direction, a sumrule holds between the increase in optical spectral weight in the Drude component and that lost in the interband optical transitions. For the nonrelativistic direction, no such sumrule applies. Results are also presented when an energy gap opens in the energy dispersion. Numerical results due to finite residual scattering are provided and analytic results for the dc limit are derived. Energy dependence and possible anisotropy in the impurity scattering rate is considered. Throughout, we provide comparison of our results for $\sqrt{{\sigma }_{xx}{\sigma }_{yy}}$ with the corresponding results for graphene. A generalization of the 2D Hamiltonian to include powers of higher order than quadratic (nonrelativistic) and linear (relativistic) is considered. We also discuss the modifications introduced when an additional flat band is included via a semi-Dirac version of the $\alpha$-${\mathcal{T}}_3$ model, for which an $\alpha$ parameter tunes between the 2D semi-Dirac (graphene-like) limit and the semi-Dirac version of the dice or ${\mathcal{T}}_3$ lattice.

17 pages, 12 figures

References in corpus (20)

• Electric Field Effect in Atomically Thin Carbon Films
• Two Dimensional Atomic Crystals
• Unconventional Integer Quantum Hall effect in graphene
• Tilted anisotropic Dirac cones in quinoid-type graphene and alpha-(BEDT-TTF)_2I_3
• Merging of Dirac points in a two-dimensional crystal
• On the universal AC optical background in graphene
• Thermoelectric properties of Weyl and Dirac semimetals
• Chiral anomaly and optical absorption in Weyl semimetals
• Optical conductivity of bilayer graphene with and without an asymmetry gap
• Semiconducting-to-metallic photoconductivity crossover and temperature-dependent Drude weight in graphene
• Optical Signatures of the Tunable Band Gap and Valley-Spin Coupling in Silicene
• Dynamical conductivity of AA-stacked bilayer graphene
• Magneto-optics of massless Kane fermions: Role of the flat band and unusual Berry phase
• Low frequency optical conductivity in graphene and in other scale-invariant two-band systems
• Temperature dependence of the conductivity of ballistic graphene
• Electrodynamic response of type II Weyl semimetals
• Interplay between topology and disorder in a two-dimensional semi-Dirac material
• Tunable orbital susceptibility in $\alpha$-${\mathcal{T}}_3$ tight-binding models
• Valley symmetry breaking and gap tuning in graphene by spin doping
• An analytic evaluation of Kane fermion magneto-optics in two and three dimensions

Cited by in corpus (3)

• Power law decay of local density of states oscillations near a line defect in a system with semi-Dirac points
• Anisotropic and tunable optical conductivity of a two-dimensional semi-Dirac system in the presence of elliptically polarized radiation
• Unfolding optical transition weights of impurity materials for first-principles LCAO electronic structure calculations