Tunneling between Edge States in a Quantum Spin Hall System

Ström, Anders; Johannesson, Henrik

doi:10.1103/physrevlett.102.096806

Cited by 103 publications

(110 citation statements)

References 25 publications

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“…Our home-built SGM probes feature self-sensing piezoresistive deflection readout [30], which allows for precise in situ alignment of the tip to the device. The separation between the contacts in the transport direction is 5 m, and the lateral mesa width is 150 m. As this width is several orders of magnitude greater than the predicted extension of the QSH edge states into the bulk [31,32], any effect of interedge tunneling [33][34][35] can be ruled out. More relevant to our SGM experiments, the large width of the device ensures that the tip-induced potential perturbation only affects the transport along the edge located within the scan window, while the far edge remains unaffected and thus provides a constant contribution to the device conductance.…”

Section: Experimental Methodsmentioning

confidence: 99%

Spatially Resolved Study of Backscattering in the Quantum Spin Hall State

et al. 2013

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The discovery of the quantum spin Hall (QSH) state, and topological insulators in general, has sparked strong experimental efforts. Transport studies of the quantum spin Hall state have confirmed the presence of edge states, showed ballistic edge transport in micron-sized samples, and demonstrated the spin polarization of the helical edge states. While these experiments have confirmed the broad theoretical model, the properties of the QSH edge states have not yet been investigated on a local scale. Using scanning gate microscopy to perturb the QSH edge states on a submicron scale, we identify well-localized scattering sites which likely limit the expected nondissipative transport in the helical edge channels. In the micron-sized regions between the scattering sites, the edge states appear to propagate unperturbed, as expected for an ideal QSH system, and are found to be robust against weak induced potential fluctuations.

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Section: Experimental Methodsmentioning

confidence: 99%

Spatially Resolved Study of Backscattering in the Quantum Spin Hall State

et al. 2013

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“…It is therefore more convenient to treat the Hamiltonian of the HLL as an effectively spinless LL by introducing the fields Φ = (φ R↑ + φ L↓ )/ √ 2 and Θ = (φ L↓ − φ R↑ )/ √ 2. When including the interactions, the bosonized form of the Hamiltonian of the interacting HLL becomes [30][31][32]70,97,98 …”

Section: B Helical Luttinger Liquidmentioning

confidence: 99%

Spectral properties of Luttinger liquids: A comparative analysis of regular, helical, and spiral Luttinger liquids

2012

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We provide analytic expressions for the Green's functions in position-frequency space as well as for the tunneling density of states of various Luttinger liquids at zero temperature: the standard spinless and spinful Luttinger liquids, the helical Luttinger liquid at the edge of a topological insulator, and the Luttinger liquid that appears either together with an ordering transition of nuclear spins in a one-dimensional conductor, or in spin-orbit split quantum wires in an external magnetic field. The latter system is often used to mimic a helical Luttinger liquid, yet we show here that it exhibits significantly different response functions and, to discriminate, we call it the spiral Luttinger liquid. We give fully analytic results for the tunneling density of state of all the Luttinger liquids as well as for most of the Green's functions. The remaining Green's functions are expressed by simple convolution integrals between analytic results.

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“…[14][15][16] So there has been a great deal of interest in the edge-state transport. [17][18][19] Consequently, the manipulation of transport for edge states by using a local electric field 20 is crucial for fundamental understanding of TI edge states and constructing dissipationless spintronic devices. In this letter, we address this important issue by studying the electronic band, density distribution, and transport for a HgTe/CdTe quantum well hall bar (strip) 13 with finite width under an electric field along the transverse y direction.…”

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confidence: 99%