Quasiballistic Transport of Dirac Fermions in a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>Bi</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Se</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>Nanowire

Dufouleur, Joseph; Veyrat, Louis; Teichgräber, A.; Neuhaus, S.; Nowka, Christian; Hampel, Silke; Cayssol, Jérôme; Schumann, J.; Eichler, Barbara; Schmidt, Oliver G.; Büchner, B.; Giraud, R.

doi:10.1103/physrevlett.110.186806

Cited by 80 publications

(147 citation statements)

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“…But notice that in metallic cylinders the h/e period AB oscillations cannot be observed due to the ensemble averaging of different slices of the metal cylinder [24,25]. The AB oscillations observed in topological nanoribbons are believed to originate from the quantum confinement and the circumferential interference of the surface states [26][27][28][29][30][31]. Moreover, the spin-helical nature of the topological surface states would introduce an additional Berry phase π as the carriers cycle along the perimeter [16,19,[32][33][34][35][36][37][38].…”

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confidence: 99%

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Gate-tuned Aharonov-Bohm interference of surface states in a quasiballistic Dirac semimetal nanowire

Lin

Wang

et al. 2017

Phys. Rev. B

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Dirac semimetals [1], such as Cd 3 As 2 or Na 3 Bi [2][3][4][5][6][7][8][9][10], show a linear electronic dispersion in three dimensions described by two copies of the Weyl equation. Applying a magnetic field can break the time reversal symmetry, and the Dirac semimetal is transformed into a Weyl semimetal with the two Weyl nodes separated in the momentum space [10,11]. Chiral charge pumping between the Weyl nodes with different chirality is predicted, which brings the Weyl fermions into the experimental realm. Recently, anomalous transport properties signaled by a pronounced negative magnetoresistance are observed as the evidence for the chiral anomaly effect [10,12].Besides this, the surface dispersion-relation of a Weyl semimetal is topologically equivalent to a non-compact Riemann surface without equal-energy contour that encloses the projection of the Weyl point [13], leading to the emergence of surface Fermi arcs [14]. Lots of angle-resolved photoemission spectroscopy (ARPES) experiments [7,[15][16][17][18] [16,19,[32][33][34][35][36][37][38]. Although the one-dimensional helical transport has been demonstrated in topological insulator nanowires through measuring the AB oscillations is the flux quantum and , where is the measured magnetic field periodicity ( in this case) and S is the cross-sectional area.From the magnetic field periodicity, we can deduce the cross-sectional area to be , which is consistent with the nanowire diameter ~58 nm. In To further clearly present the conductance oscillations, we plot the mapping of ∆G versus gate voltage and magnetic field in Fig. 1d. Clearly there are two kinds of phase modulations on the interference. One is tuned by gate voltage, and the other is influenced by the magnetic field. At a fixed gate voltage, if the conductance reaches the minimum at zero magnetic field, the conductance will be the maximum at half integer multiple of ; if the conductance is maximum at zero magnetic field, the conductance will be the maximum at integer multiple of . The phase of the AB interference is strongly dependent on gate voltage. while when the chirality is -1, the energy dispersion has a similar form with a sign 6 change. This physics picture is depicted in Fig. 2. At zero magnetic field, that is =0, the original linear energy dispersion becomes gapped with a series of sub-bands, as shown in Fig. 2a. The red and blue lines represent the chirality to be +1 and -1, respectively. According to the surface band splitting, there should emerge a periodic oscillation when the Fermi level crosses the sub-bands continuously. This is what happens in our Cd 3 As 2 nanowires, as shown in Fig. 1b.When a magnetic field is applied, the corresponding AB oscillation term should be considered. The surface energy band diagrams at the magnetic flux and are depicted in Fig. 2b, where the letter L and R denote the chirality of Weyl nodes to be +1 or −1. Apparently, when the magnetic flux is half integer of Ф 0 , the linear energy band with specified chirality emerges. The quantum transport can be...

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confidence: 99%

“…The π phase shift AB oscillations have been theoretically predicted [35,37,38] and experimentally investigated in topological insulators (TI) nanostructures [28][29][30][31]. In the presence of an axial magnetic field, the band structure of surface carriers in a TI nanostructure can be described by [30,31,35,37,38]…”

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confidence: 99%

Gate-tuned Aharonov-Bohm interference of surface states in a quasiballistic Dirac semimetal nanowire

Lin

Wang

et al. 2017

Phys. Rev. B

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“…1, has a single chiral mode reflecting from the superconductor, and is ideal for probing conductance quantization. Moreover, all of its components are readily available, as both surface transport in TI nanowires [31][32][33][34] and the contacting of bulk TI with superconductors [35][36][37] have already been demonstrated experimentally. In the remainder of this paper, we provide a detailed study of the transport properties of this system, demonstrating that conductance quantization is achievable under realistic conditions, and discuss the advantages of our setup over other proposals.…”

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confidence: 99%

Robust Transport Signatures of Topological Superconductivity in Topological Insulator Nanowires

2014

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Finding a clear signature of topological superconductivity in transport experiments remains an outstanding challenge. In this work, we propose exploiting the unique properties of threedimensional topological insulator nanowires to generate a normal-superconductor junction in the single-mode regime where an exactly quantized 2e 2 /h zero-bias conductance can be observed over a wide range of realistic system parameters. This is achieved by inducing superconductivity in half of the wire, which can be tuned at will from trivial to topological with a parallel magnetic field, while a perpendicular field is used to gap out the normal part, except for two spatially separated chiral channels. The combination of chiral mode transport and perfect Andreev reflection makes the measurement robust to moderate disorder, and the quantization of conductance survives to much higher temperatures than in tunnel junction experiments. Our proposal may be understood as a variant of a Majorana interferometer which is easily realizable in experiments.A topological superconductor is a proposed novel phase of matter with exotic properties like protected boundary states and emergent quasiparticles with non-Abelian statistics. If realized, these superconductors are expected to constitute the main building block of topological quantum computers [1]. The prototypical example of this phase, the p-wave superconductor, has proven to be difficult to find in nature, with superconducting Sr 2 RuO 4 and, indirectly, the ν = 5/2 fractional quantum Hall state among the very few conjectured candidates. While many experiments have been suggested and performed on these systems, evidence for their topological properties remains elusive. However, the recent realization that a p-wave superconductor need not be intrinsic, but can alternatively be engineered with regular s-wave superconducting proximity effect in strongly spin-orbit coupled materials [2][3][4], has opened a promising new path in the search for topological superconductivity.

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“…Therefore, interesting situations take place when TI nanostructures, such as nanowires, are realized. For a TI nanowire, the Berry phase opens a small gap at the Γ point, hampering the formation of the Dirac cone and promoting the formation of different energy sub-bands corresponding to surface states [7][8][9] . The gap gets closed for a nanowire with an infinite cross-section or with a finite cross-section upon the application of magnetic field which reduces the effects of the Berry phase 10,11 .…”

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confidence: 99%

Plasmons in topological insulator cylindrical nanowires

2017

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We present a theoretical analysis of Dirac magneto-plasmons in topological insulator nanowires. We discuss a cylindrical geometry where Berry phase effects induce the opening of a gap at the neutrality point. By taking into account surface electron wave functions introduced in previous papers and within the random phase approximation, we provide an analytical form of the dynamic structure factor. Dispersions and spectral weights of Dirac plasmons are studied with varying the radius of the cylinder, the surface doping, and the strength of an external magnetic field. We show that, at zero surface doping, inter-band damped plasmon-like excitations form at the surface and survive at low electron surface dopings (∼ 10 10 cm −2 ). Then, we point out that the plasmon excitations are sensitive to the Berry phase gap closure when an external magnetic field close to half quantum flux is introduced. Indeed, a well-defined magneto-plasmon peak is observed at lower energies upon the application of the magnetic field. Finally, the increase of the surface doping induces a crossover from damped inter-band to sharp intra-band magneto-plasmons which, as expected for large radii and dopings (∼ 10 12 cm −2 ), approach the proper limit of a two-dimensional surface.

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Quasiballistic Transport of Dirac Fermions in aBi2Se3Nanowire

Cited by 80 publications

References 39 publications

Gate-tuned Aharonov-Bohm interference of surface states in a quasiballistic Dirac semimetal nanowire

Gate-tuned Aharonov-Bohm interference of surface states in a quasiballistic Dirac semimetal nanowire

Robust Transport Signatures of Topological Superconductivity in Topological Insulator Nanowires

Plasmons in topological insulator cylindrical nanowires

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