Weak localization of two-dimensional Dirac fermions beyond the diffusion regime

Nestoklon, M. O.; Аверкиев, Н. С.; Tarasenko, S. V.

doi:10.1016/j.ssc.2011.07.031

Cited by 18 publications

(23 citation statements)

References 30 publications

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“…4,5 One of intriguing transport features of topological insulators is the weak antilocalization (WAL), appearing as the negative magnetoconductivity with a sharp cusp in low fields. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] WAL is intrinsic to topological insulators: (i) so far, most samples have low mobility and long coherence length, making the quantum interference an important correction to the diffusion transport; (ii) due to the spinmomentum locking resulted from strong spin-orbit coupling, the single gapless Dirac cone of the topological surface states carries a π Berry phase, 21,22 which changes the interference of time-reversed scattering loops from constructive to destructive. The destructive interference will give the conductivity an enhancement, which can be destroyed by applying a magnetic field that breaks the π Berry phase, leading to the negative magnetoconductivity with the cusp.…”

Section: Introductionmentioning

confidence: 99%

Weak localization of bulk channels in topological insulator thin films

2011

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Weak antilocalization (WAL) is expected whenever strong spin-orbit coupling or scattering comes into play. Spin-orbit coupling in the bulk states of a topological insulator is very strong, enough to result in the topological phase transition. However, the recently observed WAL in topological insulators seems to have an ambiguous origin from the bulk states. Starting from the effective model for three-dimensional topological insulators, we find that the lowest two-dimensional (2D) bulk subbands of a topological insulator thin film can be described by the modified massive Dirac model. We derive the magnetoconductivity formula for both the 2D bulk subbands and surface bands. Because with relatively large gap, the 2D bulk subbands may lie in the regimes where the unitary behavior or even weak localization (WL) is also expected, instead of always WAL. As a result, the bulk states may contribute small magnetoconductivity or even compensate the WAL from the surface states. Inflection in magnetoconductivity curves may appear when the bulk WL channels outnumber the surface WAL channels, providing a signature of the weak localization from the bulk states.

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Section: Introductionmentioning

confidence: 99%

Weak localization of bulk channels in topological insulator thin films

2011

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“…4 by dashed lines. It is well known that the diffusion approximation does not describe the magnetoconductivity in fields B B 0 [10,29]. Our calculation demonstrates that diffusion approximation satisfactorily describes the magnetic field dependence of the conductivity correction up to (0.02 .…”

Section: B Magnetoconductivitymentioning

confidence: 60%

“…[29] for the spectrum consisting of a single massless Dirac cone. A single-cone result for the considered twosubband system at R = 1 follows from the zero density of states of the subband s = + (the Fermi wavevector for it is equal to zero).…”

Section: Resultsmentioning

confidence: 99%

Weak antilocalization in two-dimensional systems with large Rashba splitting

Golub¹,

Gornyi²,

Kachorovskii³

2016

Phys. Rev. B

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We develop the theory of quantum transport and magnetoconductivity for two-dimensional electrons with an arbitrary large (even exceeding the Fermi energy), linear-in-momentum Rashba or Dresselhaus spin-orbit splitting. For short-range disorder potential, we derive the analytical expression for the quantum conductivity correction, which accounts for interference processes with an arbitrary number of scattering events and is valid beyond the diffusion approximation. We demonstrate that the zero-field conductivity correction is given by the sum of the universal logarithmic "diffusive" term and a "ballistic" term. The latter is temperature independent and encodes information about spectrum properties. This information can be extracted experimentally by measuring the conductivity correction at different temperatures and electron concentrations. We calculate the quantum correction in the whole range of classically weak magnetic fields and find that the magnetoconductivity is negative both in the diffusive and in the ballistic regimes, for an arbitrary relation between the Fermi energy and the spin-orbit splitting. We also demonstrate that the magnetoconductivity changes with the Fermi energy when the Fermi level is above the "Dirac point" and does not depend on the Fermi energy when it goes below this point.

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“…We show that without or at weak magnetic fields strong temperature dependence of the resistance up to 70 K is related to weak localization effect. [9][10][11][12][13][14] We investigate this effect in a wide range of temperatures and magnetic fields and find that our data are perfectly fitted by theory.[11] The times of dephasing, intra-valley and inter-valley scattering are obtained from the fitting. Another area of strong temperature dependence of the resistance is found in the quantum Hall regime at magnetic fields with the filling factor being equal to 2, where the longitudinal resistance is zero.…”

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confidence: 99%

Strongly temperature dependent resistance of meander-patterned graphene

Vasil’eva

Смирнов

Vasilyev

et al. 2017

Applied Physics Letters

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We have studied the electronic properties of epitaxial graphene devices patterned in a meander shape with the length up to a few centimeters and the width of few tens of microns. These samples show a pronounced dependence of the resistance on temperature. Accurate comparison with theory shows that this temperature dependence originates from the weak localization effect observed over a broad temperature range from 1.5 K up to 77 K. The comparison allows us to estimate the characteristic times related to quantum interference. In addition, a large resistance enhancement with temperature is observed at the quantum Hall regime near the filling factor of 2. Record high resistance and its strong temperature dependence are favorable for the construction of bolometric photodetectors.Due to its unique properties, graphene is a promising material for constructing emitters and detectors of different frequency, including poorly developed terahertz (THz) range. THz hot electron bolometers, operating at cryogenic temperatures, were made of monolayer [1][2][3] and bilayer graphene. [4,5] However, the resistance of graphene typically depends weakly on the electron temperature, which is an obstacle to the creation of graphene-based devices with high efficiency. Recently, successful observation of bolometric signal in graphene was achieved in highly resistive samples of two different types: either in a strongly disordered graphene [6] or in a patterned sample. [7,8] In particular, epitaxial graphene on SiC patterned in a meander shape has been reported to demonstrate good performance in the terahertz region (1-3 THz). [7] In this paper we present magnetotransport studies of meander shaped samples with the ratio of the sample length to width exceeding 600. We show that without or at weak magnetic fields strong temperature dependence of the resistance up to 70 K is related to weak localization effect. [9][10][11][12][13][14] We investigate this effect in a wide range of temperatures and magnetic fields and find that our data are perfectly fitted by theory.[11] The times of dephasing, intra-valley and inter-valley scattering are obtained from the fitting. Another area of strong temperature dependence of the resistance is found in the quantum Hall regime at magnetic fields with the filling factor being equal to 2, where the longitudinal resistance is zero. The observed large temperature coefficient of the resistance in graphene near the integer QHE may be used to realize a photoresponse mechanisms related to optically induced breakdown of the quantum Hall effect.[15] These effects were investigated and confirmed in semiconductor heterostructures, but, until now, studies of graphene samples with a large ratio of length to width L/W have not been carried out.The graphene samples were obtained by sublimation at the Si face of a 4H-SiC substrate by thermal decomposition in an argon atmosphere. Raman spectroscopy shows that graphene is a monolayer with high quality. Using laser lithography, samples were patterned in meander shaped Hall dev...

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Weak localization of two-dimensional Dirac fermions beyond the diffusion regime

Cited by 18 publications

References 30 publications

Weak localization of bulk channels in topological insulator thin films

Weak localization of bulk channels in topological insulator thin films

Weak antilocalization in two-dimensional systems with large Rashba splitting

Strongly temperature dependent resistance of meander-patterned graphene

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