Theory of quasiparticle interference on the surface of a strong topological insulator

Guo, Huaiming; Franz, Marcel

doi:10.1103/physrevb.81.041102

Cited by 80 publications

(108 citation statements)

References 32 publications

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“…[12][13][14][15] In Ref. 14, the authors observed that QPI is strongest for the spin LDOS response to magnetic impurities, while the unpolarized LDOS pattern vanishes for magnetic disorder (in the first Born approximation).…”

Section: Introductionmentioning

confidence: 99%

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Multifractal nature of the surface local density of states in three-dimensional topological insulators with magnetic and nonmagnetic disorder

Foster

2012

Phys. Rev. B

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We compute the multifractal spectra associated to local density of states (LDOS) fluctuations due to weak quenched disorder, for a single Dirac fermion in two spatial dimensions. Our results are relevant to the surfaces of Z2 topological insulators such as Bi2Se3 and Bi2Te3, where LDOS modulations can be directly probed via scanning tunneling microscopy. We find a qualitative difference in spectra obtained for magnetic versus non-magnetic disorder. Randomly polarized magnetic impurities induce quadratic multifractality at first order in the impurity density; by contrast, no operator exhibits multifractal scaling at this order for a non-magnetic impurity profile. For the time-reversal invariant case, we compute the first non-trivial multifractal correction, which appears at two loops (impurity density squared). We discuss spectral enhancement approaching the Dirac point due to renormalization, and we survey known results for the opposite limit of strong disorder.

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Section: Introductionmentioning

confidence: 99%

“…There are several ways of analyzing such data. One is to look for quasiparticle interference (QPI) [11][12][13][14][15] in the LDOS Fourier transform. This method is useful for determining short-distance details, and contains similar information as an analysis of LDOS Friedel oscillations in the presence of a single impurity.…”

Section: Introductionmentioning

confidence: 99%

Multifractal nature of the surface local density of states in three-dimensional topological insulators with magnetic and nonmagnetic disorder

Foster

2012

Phys. Rev. B

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“…Theories have recently been formulated to describe the quasiparticle interference seen in STM experiments, accounting for the absence of backscattering. [70][71][72] Related developments have seen the imaging of a surface bound state using scanning tunneling microscopy. 73 These experimental studies provide evidence of time-reversal symmetry protection of the chiral surface states.…”

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 lack of backscattering was established theoretically early on within a two-dimensional (2D) continuum model for the surface state [4][5][6] and later also confirmed in experiments. [7][8][9] The same 2D surface continuum model finds that, while a local impurity-induced resonance state exists for a potential impurity, its weight diminish as the energy approaches the Dirac point for unitary scatterers and the Dirac point is left unperturbed.…”

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confidence: 99%

Subsurface impurities and vacancies in a three-dimensional topological insulator

Black‐Schaffer

Balatsky

2012

Phys. Rev. B

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Using a three-dimensional microscopic lattice model of a strong topological insulator (TI) we study potential impurities and vacancies in surface, subsurface, and bulk positions. For all impurity locations we find impurityinduced resonance states with energy proportional to the inverse of the impurity strength, although the impurity strength needed for a low-energy resonance state increases with the depth of the impurity. For strong impurities and vacancies as deep as 15 layers into the material, resonance peaks will appear at and around the Dirac point in the surface energy spectrum, splitting the original Dirac point into two nodes located off-center. Furthermore, we study vacancy clusters buried deep inside the bulk and find zero-energy resonance states for both single and multiple-site vacancies. Only fully symmetric multiple-site vacancy clusters show resonance states expelled from the bulk gap.

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Theory of quasiparticle interference on the surface of a strong topological insulator

Cited by 80 publications

References 32 publications

Multifractal nature of the surface local density of states in three-dimensional topological insulators with magnetic and nonmagnetic disorder

Multifractal nature of the surface local density of states in three-dimensional topological insulators with magnetic and nonmagnetic disorder

Two-dimensional surface charge transport in topological insulators

Subsurface impurities and vacancies in a three-dimensional topological insulator

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