Magnetotransport of Dirac fermions on the surface of a topological insulator

Mondal, Sayan; Sen, Diptiman; Sengupta, K.; Shankar, Ravi

doi:10.1103/physrevb.82.045120

Cited by 59 publications

(67 citation statements)

References 39 publications

(34 reference statements)

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“…Additional spintronic functionalities can be expected from introducing ferromagnetic impurities, which are suggested to break time-reversal symmetry, thereby opening a gap in the TSS. This is of interest for devices, such as transistors, as well as for achieving the quantum anomalous Hall state [10][11][12][13][14][15][16][17] . However, their experimental realization has proven challenging and has led to yet another controversy in the literature, i.e., whether adding ferromagnetic impurities in a TI can indeed open a band gap in the TSS [18][19][20][21][22][23][24][25][26] .…”

Section: Introductionmentioning

confidence: 99%

Topological surface state of α−Sn on InSb(001) as studied by photoemission

et al. 2018

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We report on the electronic structure of the elemental topological semimetal α-Sn on InSb(001). High-resolution angle-resolved photoemission data allow to observe the topological surface state (TSS) that is degenerate with the bulk band structure and show that the former is unaffected by different surface reconstructions. An unintentional p-type doping of the as-grown films was compensated by deposition of potassium or tellurium after the growth, thereby shifting the Dirac point of the surface state below the Fermi level. We show that, while having the potential to break time-reversal symmetry, iron impurities with a coverage of up to 0.25 monolayers do not have any further impact on the surface state beyond that of K or Te. Furthermore, we have measured the spin-momentum locking of electrons from the TSS by means of spin-resolved photoemission. Our results show that the spin vector lies fully in-plane, but it also has a finite radial component. Finally, we analyze the decay of photoholes introduced in the photoemission process, and by this gain insight into the many-body interactions in the system. Surprisingly, we extract quasiparticle lifetimes comparable to other topological materials where the TSS is located within a bulk band gap. We argue that the main decay of photoholes is caused by intraband scattering, while scattering into bulk states is suppressed due to different orbital symmetries of bulk and surface states.

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Section: Introductionmentioning

confidence: 99%

Topological surface state of α−Sn on InSb(001) as studied by photoemission

et al. 2018

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“…The only transport theories we are aware of have been Ref. 83, which focused on magnetotransport in the impurity-free limit, and Ref. 84, which focused on spin-charge coupling.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional surface charge transport in topological insulators

et al. 2010

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We construct a theory of charge transport by the surface states of topological insulators in three dimensions. The focus is on the experimentally relevant case when the Fermi energy εF and transport scattering time τ satisfy εF τ / 1, but εF lies below the bottom of the conduction band. Our theory is based on the spin density matrix and takes the quantum Liouville equation as its starting point. The scattering term is determined to linear order in the impurity density ni and explicitly accounts for the absence of backscattering, while screening is included in the random phase approximation. The main contribution to the conductivity is ∝ n −1 i and has different carrier density dependencies for different forms of scattering, while an additional contribution is independent of ni. The dominant scattering angles can be inferred by studying the ratio of the transport time to the Bloch lifetime as a function of the Wigner-Seitz radius rs. The current generates a spin polarization that could provide a smoking-gun signature of surface state transport. We also discuss the effect on the surface states of adding metallic contacts.

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“…The Landau levels of topological insulators have been calculated [27,26] and bear a striking similarity to those of graphene [22,9,12,23]. There are however two important differences.…”

Section: Theorymentioning

confidence: 99%

The stability of the fractional quantum Hall effect in topological insulators

DaSilva

2011

Solid State Communications

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With the recent observation of graphene-like Landau levels at the surface of topological insulators, the possibility of fractional quantum Hall effect, which is a fundamental signature of strong correlations, has become of interest. Some experiments have reported intra-Landau level structure that is suggestive of fractional quantum Hall effect. This paper discusses the feasibility of fractional quantum Hall effect from a theoretical perspective, and argues that while this effect should occur, ideally, in the n = 0 and |n| = 1 Landau levels, it is ruled out in higher |n| Landau levels. Unlike graphene, the fractional quantum Hall effect in topological insulators is predicted to show an interesting asymmetry between n = 1 and n = −1 Landau levels due to spin-orbit coupling.

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Magnetotransport of Dirac fermions on the surface of a topological insulator

Cited by 59 publications

References 39 publications

Topological surface state of α−Sn on InSb(001) as studied by photoemission

Topological surface state of α−Sn on InSb(001) as studied by photoemission

Two-dimensional surface charge transport in topological insulators

The stability of the fractional quantum Hall effect in topological insulators

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