Temperature- and frequency-dependent optical and transport conductivities in doped buckled honeycomb lattices

Iurov, Andrii; Gumbs, Godfrey; Huang, Danhong

doi:10.1103/physrevb.98.075414

Cited by 27 publications

(19 citation statements)

References 83 publications

(63 reference statements)

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“…4(a) reveals that a high plateau starting nearly from ω = E F extends well into a high-frequency region, and it is slightly enhanced by laser irradiation from the result 1 + 4λ 4 0 for graphene. 57,58 This is in correspondence with an appearance of Landau damping for plasmon modes in the q → 0 limit, as displayed in Fig. 3(c).…”

Section: (B) and Its Insetsupporting

confidence: 83%

Quantum-statistical theory for laser-tuned transport and optical conductivities of dressed electrons in α−T3 materials

et al. 2020

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In the presence of external off-resonance and circularly-polarized irradiation, we have derived a many-body formalism and performed a detailed numerical analysis for both the conduction and optical currents in α − T3 lattices. The calculated complex many-body dielectric function, as well as conductivities of displacement and transport currents, display strong dependence on the latticestructure parameter α, especially approaching the graphene limit with α → 0. Unique features in dispersion and damping of plasmon modes are observed with different α values, which are further accompanied by a reduced transport conductivity under irradiation. The discovery in this paper can be used for designing novel multi-functional nanoelectronic and nanoplasmonic devices. I. INTRODUCTIONSo far, the α − T 3 model seems to present prospective opportunities for revolutionizing low-dimensional physics through novel two-dimensional (2D) materials. 1 Its atomic configuration consists of a graphene-type honeycomb lattice along with an additional site, i.e., a hub atom at the center of each hexagon. 2 An essential structure parameter α = tan φ, which enters into the low-energy Dirac-Weyl pseudospin-1 Hamiltonian for α − T 3 model, is found to be the ratio between the rim-to-hub and rim-to-rim hopping coefficients. This parameter affects all fundamental electronic properties of the α − T 3 lattice through topological characteristics embedded in its pseudospin-1 wave functions. Parameter α can vary from 0 to 1, corresponding to different types of α − T 3 materials, and the control of it could lead to some important technological applications for electronic and optoelectronic devices. Here, the case with α = 0 relates to graphene with a completely separated flat band, whereas α = 1 results in a pseudospin-1 dice lattice which has been fabricated and studied considerably. 3,4 Consequently, the α − T 3 model may be viewed as an interpolation between graphene and the dice lattice (or pseudospin-1 T 3 model). Its low-energy dispersion consists of a Dirac cone, similar to that for graphene, 5 as well as a flat band with zero-energy separating the valence from the conduction band for these pseudospin-1 materials. 6,7 In recent years, there have been numerous attempts for experimental realization of the α − T 3 model. Its topological characteristics, i.e., a Dirac cone with three bands touching at a single point, was observed in the triplon band structure of SrCu 2 (BO 3 ) 2 , as an example of general Mott-Hubbard insulators. 8 Moreover, dielectric photonic crystals with zero refractive index also display Dirac cone dispersion at the center of the Brillouin zone under an accidental degeneracy. 9,10 Most importantly, there exist various types of photonic Lieb lattices, 11,12 consisting of a 2D array of optical waveguides. Such waveguide-lattice structure is shown to have a three-band structure, including a perfectly flat middle band.Further to a relatively recent proposal on α − T 3 model, there have been a lot of crucial publications devoted to inv...

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Section: (B) and Its Insetsupporting

confidence: 83%

Quantum-statistical theory for laser-tuned transport and optical conductivities of dressed electrons in α−T3 materials

et al. 2020

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“…This term cannot be found in the quasiparticle relaxation time in single bubble diagram, and it together with the chiral term determines the scattering cross section [52]. While for the gapless Dirac system, like the intrinsic graphene, both the forward and backward scattering are supressed, as calculated by literatures [52,65,66]. The Boltzmann transport theory gives the following inversed relaxation time (in second order Born approximation) 1 τ p = 2π…”

Section: Pair Propagator and Relaxation Time At Finite Temperaturementioning

confidence: 99%

Attractive polaron formed in doped nonchiral/chiral parabolic system within ladder approximation

2020

Physica B: Condensed Matter

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We investigate the properties of attractive polaron formed by a single impurity dressed with the particle-hole excitations in a three-dimensional (3D) doped (extrinsic) parabolic system. Base on the single particle-hole variational ansatz, we study the pair propagator, self-energy, and the non-self-consistent medium T -matrix. The non-self-consistent T -matrix discussed in this paper contains only the open channel since we don't consider the shift of center-of-mass due to the resonance (e.g., induced by the magnetic field). Besides, since we focus on the low-density regime of the majority particles, the effective Fermi wave vector is small. The scattering form factor is discussed in detail for the chiral case and compared to the non-chiral one. The effects of the bare coupling strength, which is momentum-cutoff-dependent, are also discussed. We found that the pair propagator and the related quantities, like the self-energy, spectral function, induced effective mass, and residue (spectral weight), all exhibit different features in the low-momentum regime and the high one, which also related to the polaronic instabilities as well as the many-body fluctuation and nonadiabatic/adiabatic dynamics. The pair-propagator and the energy relaxation time at finite temperature are also explored.

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“…On the other hand, for gapped (Δ β ¼ Δ 0 ) but undoped (E F ¼ 0) graphene at high T (k B T ≫ Δ 0 and ħω), we get its optical conductivity [41] Re σ…”

Section: Thermal Plasmons In Graphene and Other Materialsmentioning

confidence: 95%

Thermal Collective Excitations in Novel Two-Dimensional Dirac-Cone Materials

Iurov¹,

Gumbs²,

Huang³

2020

Nanoplasmonics

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The purpose of this chapter is to review some important, recent theoretical discoveries regarding the effect of temperature on the property of plasmons. These include their dispersion relations and Landau damping rates, and the explicit dependence of plasmon frequency on chemical potential at finite temperatures for a diverse group of recently discovered Dirac-cone materials. These novel materials cover gapped graphene, buckled howycomb lattices (such as silicene and germanene), molybdenum disulfide and other transition-metal dichalcogenides, especially the newest dice and α-T 3 materials. The most crucial part of this review is a set of implicit analytical expressions about the exact chemical potential for each of considered materials, which greatly affects the plasmon dispersions and a lot of many-body quantum-statistical properties. We have also obtained the nonlocal plasmon modes of graphene which are further Coulomb-coupled to the surface of a thick conducting substrate, while the whole system is kept at a finite temperature. An especially rich physics feature is found for α-T 3 materials, where each of the above-mentioned properties depends on both the hopping parameter α and temperature as well.

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Temperature- and frequency-dependent optical and transport conductivities in doped buckled honeycomb lattices

Cited by 27 publications

References 83 publications

Quantum-statistical theory for laser-tuned transport and optical conductivities of dressed electrons in α−T3 materials

Quantum-statistical theory for laser-tuned transport and optical conductivities of dressed electrons in α−T3 materials

Attractive polaron formed in doped nonchiral/chiral parabolic system within ladder approximation

Thermal Collective Excitations in Novel Two-Dimensional Dirac-Cone Materials

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