Optical conductivity of topological insulator thin films in a quantizing magnetic field

Ullah, Ahsan; Sabeeh, K.

doi:10.1088/0953-8984/26/50/505303

Cited by 15 publications

(17 citation statements)

References 42 publications

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“…In Fig. (15) and Fig. (16) we show real part of σ xy (ω) as a function of ω, we find that real part of σ xy (ω) exhibits sharp cyclotron resonance peaks at transition energies for transition involving n = 0 LL.…”

Section: Optical Hall Conductivitymentioning

confidence: 79%

“…In addition to gap tuning, another advantage of thin films is that their bulk contribution is small and allows observation of surface properties of topological insulators [7][8][9]. In earlier work, it was revealed that thin film topological insulators show interesting physics when time reversal symmetry is broken; either by magnetic ordering or by the application of external magnetic field [10][11][12][13][14][15]. It was shown that through gap tuning, the system can make a transition from the normal insulator(NI) to a TI phase with finite dc Hall conductivity [11,13,15].…”

Section: Introductionmentioning

confidence: 99%

“…In the rest of the paper we will not consider the effect of magnetic ordering. The Hamiltonian of our system takes the form [13,15],…”

Section: Introductionmentioning

confidence: 99%

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Magneto-optical properties of topological insulator thin films with broken inversion symmetry

Rahim

Ullah

Tahir

et al. 2017

J. Phys.: Condens. Matter

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We determine the optical response of ultrathin film topological insulators in the presence of a quantizing external magnetic field taking into account both hybridization between surface states, broken inversion symmetry and explicit time reversal symmetry breaking by the magnetic field. We find that breaking of inversion symmetry in the system, which can be due to interaction with a substrate or electrical gating, results in Landau level crossings which lead to additional optical transition channels that were previously forbidden. We show that by tuning the hybridization and symmetry breaking parameters, a transition from the normal to a topological insulator phase occurs with measureable signatures in both the longitudinal and optical Hall conductivity.

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Section: Optical Hall Conductivitymentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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Magneto-optical properties of topological insulator thin films with broken inversion symmetry

Rahim

Ullah

Tahir

et al. 2017

J. Phys.: Condens. Matter

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“…It has been shown that the effect of the thickness becomes important when it is less than 5 nm [23][24][25][26][27]. Further, thermoelectric effects [28] and optical properties [29] of TI thin films have also been studied. Due to their unique band structure, TIs are ideal candidates for observing relativistic quantum effects predicted by the Dirac equation, like Klein's paradox and the zitterbewegung of electrons.…”

Section: Introductionmentioning

confidence: 99%

Hybridization effects on wave packet dynamics in topological insulator thin films

Abdullah¹,

Naeem²,

Khan³

et al. 2017

J. Phys.: Condens. Matter

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Theoretical study of electron wave packet dynamics in topological insulator (TI) thin films is presented. We have investigated real space trajectories and spin dynamics of electron wave packets in TI thin films. Our focus is on the role of hybridization between the electronic states of the two surfaces. This allows us to access the crossover regime of a thick film with no hybridization to a thin film with finite hybridization. We show that the electron wave packet undergoes side-jump motion in addition to zitterbewegung. The oscillation frequency of zitterbewegung can be tuned by the strength of hybridization, which in turn can be tuned by the thickness of the film. We find that the spin expectations also exhibit zitterbewegung tunable by hybridization. We also show that it is possible to obtain persistent zitterbewegung, oscillations which do not decay, in both the real space trajectories as well as spin dynamics. The zitterbewegung oscillation frequency in TI thin films falls in a parameter regime where it might be possible to observe these effects using present day experimental techniques.

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“…Under a perpendicular magnetic field B, graphene exhibits a √ B-dependent Landau level (LL) spectrum and gives rise to an unusual integer quantum Hall effect (QHE). Similar to graphene, the n 0 LLs of silicene scale as √ B, whereas the n = 0 LL is not pinned at zero energy as in graphene [11,12]. Therefore, silicene is expected to exhibit an exotic QHE, and the n = 0 LL should possess peculiar properties under the combination of a perpendicular electric field and the spin-orbit interaction (SOI).…”

Section: Introductionmentioning

confidence: 99%

Integer quantum Hall effect and topological phase transitions in silicene

Liu¹,

Luo²,

Xu³

et al. 2017

Condens. Matter Phys.

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We numerically investigate the effects of disorder on the quantum Hall effect (QHE) and the quantum phase transitions in silicene based on a lattice model. It is shown that for a clean sample, silicene exhibits an unconventional QHE near the band center, with plateaus developing at ν = 0, ±2, ±6, . . . , and a conventional QHE near the band edges. In the presence of disorder, the Hall plateaus can be destroyed through the float-up of extended levels toward the band center, in which higher plateaus disappear first. However, the center ν = 0Hall plateau is more sensitive to disorder and disappears at a relatively weak disorder strength. Moreover, the combination of an electric field and the intrinsic spin-orbit interaction (SOI) can lead to quantum phase transitions from a topological insulator to a band insulator at the charge neutrality point (CNP), accompanied by additional quantum Hall conductivity plateaus.

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Optical conductivity of topological insulator thin films in a quantizing magnetic field

Cited by 15 publications

References 42 publications

Magneto-optical properties of topological insulator thin films with broken inversion symmetry

Magneto-optical properties of topological insulator thin films with broken inversion symmetry

Hybridization effects on wave packet dynamics in topological insulator thin films

Integer quantum Hall effect and topological phase transitions in silicene

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