Chiral Majorana edge states in HgTe quantum wells

Weithofer, Luzie; Recher, Patrik

doi:10.1088/1367-2630/15/8/085008

Cited by 27 publications

(27 citation statements)

References 51 publications

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“…We estimate the energy of the nonlocal fermion of the T junction from the numerical data as ξ = 8 µeV. The numerical data is indeed consistent with a splitting of adjacent Majoranas of 14 …”

Section: Microscopic Modelmentioning

confidence: 52%

Electron transport in multiterminal networks of Majorana bound states

2014

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We investigate electron transport through multiterminal networks hosting Majorana bound states (MBS) in the framework of full counting statistics (FCS). In particular, we apply our general results to T-shaped junctions of two Majorana nanowires. When the wires are in the topologically nontrivial regime, three MBS are localized near the outer ends of the wires, while one MBS is localized near the crossing point, and when the lengths of the wires are finite adjacent MBS can overlap. We propose a combination of current and cross-correlation measurements to reveal the predicted coupling of four Majoranas in a topological T junction. Interestingly, we show that the elementary transport processes at the central lead are different compared to the outer leads, giving rise to characteristic non-local signatures in electronic transport. We find quantitative agreement between our analytical model and numerical simulations of a tight-binding model. Using the numerical simulations, we discuss the effect of weak disorder on the current and the cross-correlation functions.

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Section: Microscopic Modelmentioning

confidence: 52%

Electron transport in multiterminal networks of Majorana bound states

2014

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“…Time-reversal symmetry allows for non-zero off-diagonal terms in the bulk Hamiltonian due to the presence of bulk [32][33][34][35] or interface [36,37] inversion asymmetry. These off-diagonal terms result in a splitting of the electron and heavy-hole states, which has been measured recently in CdTe/HgTe/CdTe [38,39].…”

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confidence: 99%

Helical edge transport in the presence of a magnetic impurity

Kurilovich

Burmistrov

et al. 2017

Jetp Lett.

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We consider the effects of electron scattering off a quantum magnetic impurity on the current-voltage characteristics of the helical edge of a two-dimensional topological insulator. We compute the backscattering contribution to the current along the edge for a general form of the exchange interaction matrix and arbitrary value of the magnetic impurity spin. We find that the differential conductance may exhibit a non-monotonous dependence on the voltage with several extrema. PACS:Introduction. -Two-dimensional topological insulators (2D TIs) are in the focus of recent interest due to existence of two helical edge states inside the band gap [1,2]. Because of spin-momentum locking caused by strong spin-orbit coupling, electrical current transfers helicity along the edge [3,4]. This "spin" current is a hallmark of the quantum spin Hall effect, and it has been detected experimentally in HgTe/CdTe quantum wells [5][6][7][8][9]. If only elastic scattering is allowed, and in the absence of time-reversal symmetry breaking, the helical state is a realization of the ideal transport channel with conductance of G 0 = e 2 /h. This prediction was questioned by the experiments in HgTe/CdTe [5,[10][11][12] and InAs/GaSb [13,14] quantum wells. Therefore, studies of mechanisms which can lead to the destruction of the ideal helical transport are important.A local perturbation breaking the time-reversal symmetry, e.g., a classical magnetic impurity, leads to backscattering of helical edge states and reduction of the edge conductance [15,16]. Electron-electron interactions along the edge can promote edge reconstruction and, consequently, spontaneous time-reversal symmetry breaking at the edge [17]. Furthermore, even in the absence of time-reversal symmetry breaking, electronelectron interactions may induce backscattering [18], resulting in the suppression of the helical edge conductance at finite temperatures (see [19] and references therein). A combination of electron-electron interactions and magnetic impurities can significantly modify the picture of ideal helical edge transport [20][21][22][23][24].In the absence of electron-electron interactions along the edge, the ideal transport along the helical edge may

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“…Therefore, the coupling matrix element between E1 and HH1 is nonzero, and these subbands must anticross rather than cross at zero in-plane wave vector k. As pointed out in Refs. [17][18][19][20] in the case of HgTe/CdTe QWs a reduction in symmetry leads to the splitting of states at k = 0. However, a theory identifying the source of the splitting (bulk vs inter-face) and predicting its magnitude has been lacking.…”

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confidence: 99%

Split Dirac cones in HgTe/CdTe quantum wells due to symmetry-enforced level anticrossing at interfaces

Tarasenko¹,

Durnev²,

Nestoklon³

et al. 2015

Phys. Rev. B

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We describe the fine structure of Dirac states in HgTe/CdHgTe quantum wells of critical and close-to-critical thickness and demonstrate the formation of an anticrossing gap between the tips of the Dirac cones driven by interface inversion asymmetry. By combining symmetry analysis, atomistic calculations, and k•p theory with interface terms, we obtain a quantitative description of the energy spectrum and extract the interface mixing coefficient. The zero-magnetic-field splitting of Dirac cones can be experimentally revealed in studying magnetotransport phenomena, cyclotron resonance, Raman scattering, or THz radiation absorption.

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Chiral Majorana edge states in HgTe quantum wells

Cited by 27 publications

References 51 publications

Electron transport in multiterminal networks of Majorana bound states

Electron transport in multiterminal networks of Majorana bound states

Helical edge transport in the presence of a magnetic impurity

Split Dirac cones in HgTe/CdTe quantum wells due to symmetry-enforced level anticrossing at interfaces

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