Floquet engineering of tilted and gapped Dirac bandstructure in 1T$$^\prime$$-MoS$$_2$$

Abstract

We have developed a rigorous theoretical formalism for Floquet engineering, investigating, and subsequently tailoring most crucial electronic properties of 1T$$^\prime$$ ′ -MoS$$_2$$ 2 by applying an external high-frequency dressing field within the off-resonance regime. It was recently demonstrated that monolayer semiconducting 1T$$^\prime$$ ′ -MoS$$_2$$ 2 exhibits tunable and gapped spin- and valley-polarized tilted Dirac bands. The electron-photon dressed states depend strongly on the polarization of the applied irradiation and reflect a full complexity of the low-energy Hamiltonian for non-irradiated material. We have calculated and analyzed the properties of the electron dressed states corresponding to linear and circular polarization of a dressing field by focusing on their symmetry, anisotropy, tilting, direct and indirect band gaps. Circularly polarized dressing field is known for transition into a new electronic state with broken time-reversal symmetry and a non-zero Chern number, and therefore, the combination of these topologically non-trivial phases and transitions between them could reveal some truly unique and previously unknown phenomena and applications. We have also computed and discussed the density of states for various types of 1T$$^\prime$$ ′ -MoS$$_2$$ 2 materials and its modification in the presence of a dressing field.

Optical conductivity of gapped α−T3 materials with a deformed flat band

“…Such a non-trivial bandgap, which affects all three bands of α-T 3 , will show up after applying an external off-resonance dressing field with a circular or an elliptical polarization. 17,[56][57][58] The low-energy states in α − T 3 model which belong to a Dirac cone (not the flat band) are chiral, similarly to the corresponding states in graphene. The band structure, which consists of the Dirac cone together with the flat band, does not describe the whole complexity of the system, but this approximation works fairly well for the low energies of electrons close to the Dirac cone.…”

Application of WKB Theory to Investigating Electron Tunneling in Kek-Y Graphene

“…However, a linearly-polarized irradiation normally does not affect the gap although it can induce or modify the existing anisotropy [69,70]. Interestingly, the effects of these external fields with different polarizations could further mix with anisotropic and tilted energy dispersions of lattices, such as 1T MoS 2 [71][72][73].…”

Floquet Modification of the Bandgaps and Energy Spectrum in Flat-Band Pseudospin-1 Dirac Materials

“…[11] Floquet theory has been successfully applied to original, [12][13][14][15][16][17] gapped [13,18] and Kekulepatterned graphene. [19] It also enters into extensive studies of anisotropic [20] and tilted Dirac materials [21][22][23][24][25][26][27] as well as other structures. [12,[28][29][30][31][32].…”