Interplay between topology and disorder in a two-dimensional semi-Dirac material

Sriluckshmy, P. V.; Saha, Kush; Moessner, Roderich

doi:10.1103/physrevb.97.024204

Cited by 38 publications

(29 citation statements)

References 47 publications

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“…3(a). A similar transition flow has been reported in other topological models but not the HHH model [10,13,15,16,18,21].…”

Section: Disorder Phase Diagram Of the Hhh Modelsupporting

confidence: 86%

Disorder-induced Chern insulator in the Harper-Hofstadter-Hatsugai model

Kuno

2019

Phys. Rev. B

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We study the effects of disorder on the topological Chern insulating phase in the Harper-Hofstadter-Hatsugai (HHH) model. The model with half flux has a bulk band gap and thus exhibits a nontrivial topological phase. We consider two typical types of disorder: on-site random disorder and the Aubry-Andre type quasi-periodic potential. Using the coupling matrix method, we clarify the global topological phase diagram in terms of the Chern number. The disorder modifies the gap closing behavior of the system. This modification induces the Chern insulating phase even in the trivial phase parameter regime of the system in the clean limit. Moreover, we consider an interacting Rice-Mele model with disorder, which can be obtained by dimensional reduction of the HHH model. Moderately strong disorder leads to an increase in revival events of the Chern insulator at a specific parameter point.

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“…3(a). A similar transition flow has been reported in other topological models but not the HHH model [10,13,15,16,18,21].…”

Section: Disorder Phase Diagram Of the Hhh Modelsupporting

confidence: 86%

Disorder-induced Chern insulator in the Harper-Hofstadter-Hatsugai model

Kuno

2019

Phys. Rev. B

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“…In the undeformed HM, such transition occurs only at the point M = 0 and Φ = 0. This feature is reminiscent of the result found in the case of the Chern insulator on a square lattice 51 and in disordered semi-Dirac material 23 . At the critical value ǫ = 0.5, the hopping parameter t ′ vanishes (Eq.4) as found in Ref.…”

Section: Haldane Model Under Strain: Phase Diagramsupporting

confidence: 70%

Strain tuned topology in the Haldane and the modified Haldane models

Mannaï

Haddad

2020

J. Phys.: Condens. Matter

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We study the interplay between a uniaxial strain and the topology of the Haldane and the modified Haldane models which, respectively, exhibit chiral and antichiral edge modes. The latter were, recently, predicted by Colomés and Franz (Phys. Rev. Lett. 120, 086603 (2018)) and expected to take place in the transition metal dichalcogenides. Using the continuum approximation and a tight-binding approach, we investigate the effect of the strain on the topological phases and the corresponding edge modes. We show that the strain could induce transitions between topological phases with opposite Chern numbers or tune a topological phase into a trivial one. As a consequence, the dispersions of the chiral and antichiral edge modes are found to be strain dependent. The strain may reverse the direction of propagation of these modes and eventually destroy them. This effect may be used for strain-tunable edge currents in topological insulators and two-dimensional transition metal dichalcogenides.

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“…For instance, the transmittance as a function of incident polarization angle 43 is altered in an important way, as is the dichroism 44 . Another discussion of the effect of anisotropy on transport and other properties was given by Sriluckshmy et al 45 . They treat impurity scattering in a self-consistent Born approximation and emphasise that the resulting self-energy has a nonzero offdiagonal component which leads to an enlargement of the phase diagram in a semi-Dirac material to include a two-node Chern state which is not part of the clean case.…”

Section: Introductionmentioning

confidence: 99%

Optical properties of a semi-Dirac material

2019

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Within a Kubo formalism, we calculate the absorptive part of the dynamic longitudinal conductivity σ(Ω) of a 2D semi-Dirac material. In the clean limit, we provide separate analytic formulas for intraband (Drude) and interband contributions for σ(Ω) 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 √ σxxσyy 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 α-T3 model, for which an α parameter tunes between the 2D semi-Dirac (graphene-like) limit and the semi-Dirac version of the dice or T3 lattice.

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Interplay between topology and disorder in a two-dimensional semi-Dirac material

Cited by 38 publications

References 47 publications

Disorder-induced Chern insulator in the Harper-Hofstadter-Hatsugai model

Disorder-induced Chern insulator in the Harper-Hofstadter-Hatsugai model

Strain tuned topology in the Haldane and the modified Haldane models

Optical properties of a semi-Dirac material

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