Dynamical optical conductivity for gapped $\alpha -{\mathcal{T}}_3$ materials with a curved "flat" band

Abstract

We have calculated the dynamical optical conductivity for $\alpha -{\mathcal{T}}_3$ materials in the presence of a finite bandgap in their energy bandstructure. This is a special type of energy dispersions because for all $\alpha -{\mathcal{T}}_3$ materials with a bandgap, except graphene and a dice lattice limits, the flat band receives a non-zero dispersion and assumes a curved shape. The infinite $\mathbf{k}$-degeneracy of the flat energy band is also lifted. Such a low-energy bandstructure could be obtained if an $\alpha -{\mathcal{T}}_3$ material is irradiated off-resonant with circularly polarized light. We have calculated the optical conductivity for the zero and finite temperatures, as well as for the cases of a finite and nearly-zero doping. We have demonstrated that analytical expressions could be in principle obtained for all types of gapped $\alpha -{\mathcal{T}}_3$ materials and provided the closed-form analytical expressions for a gapped dice lattice. Our numerical results reveal some well-known signatures of the optical conductivity in $\alpha -{\mathcal{T}}_3$ and silicene with two non-equivalent bandgaps, as well as demonstrate some very specific features which have not been previously found in any existing Dirac materials.

17 pages, 4 figures

References in corpus (26)

• The Valley Hall Effect in MoS2 Transistors
• Measurement of the Optical Conductivity of Graphene
• The optical conductivity of graphene in the visible region of the spectrum
• Magneto-optical conductivity in Graphene
• Observation of a localized flat-band state in a photonic Lieb lattice
• Superconductivity in the ${\mathbb{Z}}_2$ kagome metal KV${}_3$Sb${}_5$
• Ultrafast Manipulation of Valley Pseudospin
• Screening induced temperature dependent transport in 2D graphene
• On the minimal conductivity of graphene
• Topological Phases for Fermionic Cold Atoms on the Lieb Lattice
• Effect of electron-electron interactions on the conductivity of clean graphene
• Optical Signatures of the Tunable Band Gap and Valley-Spin Coupling in Silicene
• Effect of electron-hole asymmetry on optical conductivity in 8-Pmmn borophene
• Optical Conductivity of Twisted Bilayer Graphene
• Floquet topological phase transition in $\alpha$-${\mathcal{T}}_3$ lattice
• On the Relation between Optical Conductivity and Quasiparticle Dynamics: Boson Structures
• Electron states for gapped pseudospin-1 fermions in the field of charged impurity
• Dynamics of a quasiparticle in the $\alpha$-T${}_3$ model: Role of pseudospin polarization and transverse magnetic field on \textbf{\textit{zitterbewegung}}
• Anisotropic longitudinal optical conductivities of tilted Dirac bands in 1T${}^{\prime }$-MoS${}_2$
• Spin-resolved optical conductivity of two-dimensional group-VIB transition-metal dichalcogenides
• Finite-temperature plasmons, damping and collective behavior for $\alpha -{\mathcal{T}}_3$ model
• Revealing Hofstadter Spectrum for Graphene in a Periodic Potential
• Optical conductivity of semi-Dirac and pseudospin-1 models: Zitterbewegung approach
• Many-Body Effects and Optical Properties of Single- and Double Layer $\alpha$-${\mathcal{T}}_3$ Lattices
• Valley filtering in strain-induced $\alpha$-${\mathcal{T}}_3$ quantum dots
• Zigzag dice lattice ribbons: Distinct edge morphologies and structure-spectrum correspondences

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• Optical conductivity of bilayer dice lattices
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• Tuned gap in graphene through laser barrier
• Band structure and optical response of Kekulé-modulated $\alpha -{\mathcal{T}}_3$ model
• Surface states and finite size effects in triple-fold semimetals
• Floquet engineering of spin-valley selective transport in jacutingaite