Transport in three-dimensional topological insulators: Theory and experiment

Culcer, Dimitrie

doi:10.1016/j.physe.2011.11.003

Cited by 143 publications

(147 citation statements)

References 149 publications

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“…1(d)-1(g)] for x=0.10 and x=0.20 below 50K clearly indicate the changing topological character for compositions across x=0. 16. A gapped state is observed in the ARPES dispersion and momentum distribution curves for x=0.10 ( Fig.1(d,e)) whereas for x=0.20 a gapless topological Dirac surface state is clearly resolved (Fig.1(f,g)), in agreement with previous ARPES studies.…”

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confidence: 90%

“…The SdH frequency extracted from the plot of the Landau index N versus 1/B (Fig.2(c)) comes out close to 5T for x=0.19 and 2.6T for x=0.14. For x=0.19, this yields a 3D carrier density of about 6x10 16 cm -3 per valley or a total carrier density of 2.4x10 17 cm -3 for the four valleys of Pb1-xSnxSe. This also agrees with nHall≈3x10 17 cm -magnetooptical measurements on the same samples.…”

Section: Fig 2 (Color Online) (A)mentioning

confidence: 99%

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Negative Longitudinal Magnetoresistance from the Anomalous N=0 Landau Level in Topological Materials

et al. 2017

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Negative longitudinal magnetoresistance (NLMR) is shown to occur in topological materials in the extreme quantum limit, when a magnetic field is applied parallel to the excitation current. We perform pulsed and DC field measurements on Pb1-xSnxSe epilayers where the topological state can be chemically tuned. The NLMR is observed in the topological state, but is suppressed and becomes positive when the system becomes trivial. In a topological material, the lowest N=0 conduction Landau level disperses down in energy as a function of increasing magnetic field, while the N=0 valence Landau level disperses upwards. This anomalous behavior is shown to be responsible for the observed NLMR. Our work provides an explanation of the outstanding question of NLMR in topological insulators and establishes this effect as a possible hallmark of bulk conduction in topological matter. [13]. This stems from the helical Dirac nature of surface-states in 3D TIs or, that of edge-states in 2D TIs. In fact, a huge amount of literature (for reviews [14] [15] [16] [17]) took interest in this question and investigated electronic transport of 2D Dirac electrons in 3D-TIs. The majority of these studies were, however, impeded by the significant and dominant bulk transport that occurs in TIs. On the other hand, little attention has been given to signatures of non-trivial band topology in 3D electron transport in a TI.Naively speaking, one can think of the bulk energy bands of a TI as being identical to those of conventional semiconductors and, thus, unlikely to generate non-conventional physical phenomena. However, one should not forget that the basis of a topological insulator lies in the inverted orbital character of these bulk energy bands. [23] shown, that the energy of the lowest (N=0) conduction (valence) Landau level in topological insulators decreases (increases) as a function of increasing magnetic field, opposite to what usually happens in a topologically trivial system ( Fig.1(a,b)). This behavior is anomalous and leads to a field-induced closure of the energy gap in a TI [21] (Fig.1(b)), whereas in a trivial material, the energy gap usually opens with increasing magnetic field ( Fig.1(a)). This anomaly is a hallmark of the inverted band structure of topological materials. Its implications on magnetotransport have not yet been considered. In the present work, we study the MR in topological insulators in the extreme quantum limit -the regime where only the lowest Landau level (LL) is occupied. We measure magnetotransport in pulsed magnetic field up to 61T in high mobility Pb1-xSnxSe epitaxial layers. We show that, when all Lorentz components contributing to the MR are suppressed by applying the magnetic field in-plane and parallel to the excitation current, a negative longitudinal MR (NLMR) emerges near the onset of the quantum limit. This NLMR is only observed in the topological regime of Pb1-xSnxSe (x>0.16) and is absent in trivial samples (x<0.16). We theoretically argue that this NLMR is a result of the anomalous beh...

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confidence: 90%

Section: Fig 2 (Color Online) (A)mentioning

confidence: 99%

Negative Longitudinal Magnetoresistance from the Anomalous N=0 Landau Level in Topological Materials

et al. 2017

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“…The topological invariant is derived from the band structure properties of the bulk electrons, and in certain materials, sufficiently strong spin-orbit coupling causes the valence and conduction bands to invert, which results in the topological invariant to change and a topological surface states (TSS) to develop (see Ref. [1][2][3][4] and references therein). In the case of three dimensional (3D) TIs, such as Bi 2 Se 3 , and Bi 2 Te 3 , it was predicted and observed that the surface states span the bulk energy gap and have a linear Diraclike dispersion with chiral spin-momentum locking [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Transport properties of topological insulators: Band bending, bulk metal-to-insulator transition, and weak anti-localization

Brahlek

Koirala

Bansal

et al. 2015

Solid State Communications

138

172

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“…At higher energies, however, corrections like quadratic-in-momentum and anisotropic hexagonal-warping effects should be included in the effective Hamiltonian [7]. The chiral nature of these Dirac states have some peculiar implications on their transport properties [8,9]. The back-scattering of these surface electrons from impurities, and therefore the localization is forbidden as long as the impurity potential does not break the TR symmetry [10].…”

Section: Introductionmentioning

confidence: 99%

Anisotropic conductivity in magnetic topological insulators

Sabzalipour

Abouie²,

Abedinpour³

2015

J. Phys.: Condens. Matter

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Abstract. We study the surface conductivity of a three dimensional topological insulator doped with magnetic impurities. The spin-momentum locking of surface electrons makes their scattering from magnetic impurities anisotropic and the standard relaxation time approximation is not applicable. Using the semiclassical Boltzmann approach together with a generalized relaxation time scheme, we obtain closed forms for the relaxation times and analytic expressions for the surface conductivities of the system as functions of the bulk magnetization and the orientation of the aligned surface magnetic impurities. We show that the surface conductivity is anisotropic, and strongly depends both on the direction of the spins of magnetic impurities and on the magnitude of the bulk magnetization. In particular, we find that the surface conductivity has its minimum value when the spin of surface impurities are aligned perpendicular to the surface of TI, and therefore the backscattering probability is enhanced due to the magnetic torque exerted by impurities on the surface electrons.PACS numbers: 72.15.Lh

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Transport in three-dimensional topological insulators: Theory and experiment

Cited by 143 publications

References 149 publications

Negative Longitudinal Magnetoresistance from the Anomalous N=0 Landau Level in Topological Materials

Negative Longitudinal Magnetoresistance from the Anomalous N=0 Landau Level in Topological Materials

Transport properties of topological insulators: Band bending, bulk metal-to-insulator transition, and weak anti-localization

Anisotropic conductivity in magnetic topological insulators

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