Dynamics of a quasiparticle in theα-T3model: role of pseudospin polarization and transverse magnetic field onzitterbewegung

Biswas, Tutul; Ghosh, Tarun Kanti

doi:10.1088/1361-648x/aaa60b

Cited by 65 publications

(44 citation statements)

References 59 publications

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“…Then we solve numerically the system of coupled differential equations that comes from Eq. (16). For this purpose, we consider that the amplitude of the electric field has a value E 0 = 5 × 10 −2 V/m and the frequency of the electromagnetic wave is Ω = 22 GHz.…”

Section: Exact Numerical Results and Discussionmentioning

confidence: 99%

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Electron transitions for Dirac Hamiltonians with flat bands under electromagnetic radiation: Application to the α−T3 graphene model

et al. 2020

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In a system with a Dirac-like linear dispersion there are always states that fulfill the resonance condition for electromagnetic radiation of arbitrary frequency Ω. When a flat band is present two kinds of resonant transitions are found. Considering the α − T3 graphene model as a minimal model with a flat band and Dirac cones, and describing the dynamics using the interaction picture, we study the band transitions induced by an external electromagnetic field. We found that transitions depend upon the relative angle between the electron momentum and the electromagnetic field wavevector. For parallel incidence, the transitions are found using Floquet theory while for other angles perturbation theory is used. In all cases, the transition probabilities and the frequencies are found. For some special values of the parameter α or by charge doping, the system behaves as a three-level or a two-level Rabi system. All these previous results were compared with numerical simulations. A good agreement was found between both. The obtained results are useful to provide a quantum control of the system.

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Section: Exact Numerical Results and Discussionmentioning

confidence: 99%

“…This section is devoted to study the transitions that are obtained from Eq. (16). The first observation concerning Eq.…”

Section: Transitionsmentioning

confidence: 99%

Electron transitions for Dirac Hamiltonians with flat bands under electromagnetic radiation: Application to the α−T3 graphene model

et al. 2020

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“…40 The same applies to the magnetotransport of α-T 3 materials, 41 its conductivity displays several peaks, and each of those peaks is split if α is set finite. 42,43 Consequently, one of our goals here will be to study how the geometric Berry phase of an α-T 3 lattice is modified in the presence of a dressing field.…”

Section: Introductionmentioning

confidence: 99%

Peculiar electronic states, symmetries, and Berry phases in irradiated α−T3 materials

2019

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We have laid out the results of a rigorous theoretical investigation into the response of electron dressed states, i.e., interacting Floquet states arising from the off-resonant coupling of Dirac spin-1 electrons in the α-T3 model, to external radiation with various polarizations. Specifically, we have examined the role played by the parameter α that is a measure of the coupling strength with the additional atom at the center of the honeycomb graphene lattice and which, when varied, continuously gives a different Berry phase. We have found that the electronic properties of the α -T3 model (consisting of a flat band and two cones) could be modified depending on the polarization of the imposed irradiation. We have demonstrated that under elliptically-polarized light the lowenergy band structure of such lattice directly depends on the valley index τ . We have obtained and analyzed the corresponding wave functions, their symmetries and the corresponding Berry phases, and revealed that such phases could be finite even for a dice lattice, which has not been observed in the absence of the dressing field. This results lead to possible radiation-generated band structure engineering, as well as experimental and technological realization of such optoelectronic devices and photonic crystals.

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“…It has been shown that a two-dimensional (2D) model for Hg 1−x Cd x Te at critical doping can be mapped onto the α-T 3 model with an intermediate parameter α = 1/ √ 3 [56]. The α-T 3 model exhibits several unusual electronic properties such as super-Klein tunneling [65][66][67][68][69], minimal conductivity [60], orbital magnetic response [42,70], frequency-dependent magnetooptical conductivity [71,72], and Weiss oscillations [73].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear optical response of the α−T3 model due to the nontrivial topology of the band dispersion

Chen

Zuber

et al. 2019

Phys. Rev. B

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2019). Nonlinear optical response of the alpha-T-3 model due to the nontrivial topology of the band dispersion. Physical Review B, 100 (3), 035440-1-035440-16. Nonlinear optical response of the alpha-T-3 model due to the nontrivial topology of the band dispersion AbstractWe study the electronic contribution to the nonlinear optical response of the α-T3 model. This model is an interpolation between a graphene (α = 0) and dice (α = 1) lattice. Using a second-quantized formalism, we calculate the first-and third-order responses for a range of α and chemical potential values as well as considering a band gap in the first-order case. Conductivity quantization is observed for the first-order, while higher-order harmonic generation is observed in the third-order response with the chemical potential determining which applied field frequencies both quantization and harmonic generation occur at. We observe a range of experimentally accessible critical fields between 102-106 V/m with dynamics depending on α, μ, and the applied field frequency. Our results suggest an α-T3-like lattice could be an ideal candidate for use in terahertz devices.We study the electronic contribution to the nonlinear optical response of the α-T 3 model. This model is an interpolation between a graphene (α = 0) and dice (α = 1) lattice. Using a second-quantized formalism, we calculate the first-and third-order responses for a range of α and chemical potential values as well as considering a band gap in the first-order case. Conductivity quantization is observed for the first-order, while higher-order harmonic generation is observed in the third-order response with the chemical potential determining which applied field frequencies both quantization and harmonic generation occur at. We observe a range of experimentally accessible critical fields between 10 2 -10 6 V/m with dynamics depending on α, μ, and the applied field frequency. Our results suggest an α-T 3 -like lattice could be an ideal candidate for use in terahertz devices.

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Dynamics of a quasiparticle in theα-T₃model: role of pseudospin polarization and transverse magnetic field onzitterbewegung

Cited by 65 publications

References 59 publications

Electron transitions for Dirac Hamiltonians with flat bands under electromagnetic radiation: Application to the α−T3 graphene model

Electron transitions for Dirac Hamiltonians with flat bands under electromagnetic radiation: Application to the α−T3 graphene model

Peculiar electronic states, symmetries, and Berry phases in irradiated α−T3 materials

Nonlinear optical response of the α−T3 model due to the nontrivial topology of the band dispersion

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