Quantum Electronic Transport of Topological Surface States in β-Ag<sub>2</sub>Se Nanowire

Kim, Ji‐Hwan; Hwang, Ahreum; Lee, Sanghoon; Jhi, Seung-Hoon; Lee, Sunghun; Park, Yun Chang; Kim, Siin; Kim, Hong-Seok; Doh, Yong-Joo; Kim, Jinhee; Kim, Bongsoo

doi:10.1021/acsnano.5b07368

Cited by 24 publications

(22 citation statements)

References 59 publications

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“…This "shifting" of the 1D subbands with changing flux implies that for a given Fermi level position the conductance should be φ 0 -periodic. Dominating h/e oscillations were indeed observed in a number of experiments [11][12][13][14][15][16][17] . Furthermore, the phase of the Aharonov-Bohm-type oscillations depends on the Fermi level position.…”

Section: Introductionmentioning

confidence: 73%

Probing spin helical surface states in topological HgTe nanowires

et al. 2018

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Nanowires with helical surface states represent key prerequisites for observing and exploiting phase-coherent topological conductance phenomena, such as spin-momentum locked quantum transport or topological superconductivity. We demonstrate in a joint experimental and theoretical study that gated nanowires fabricated from high-mobility strained HgTe, known as a bulk topological insulator, indeed preserve the topological nature of the surface states, that moreover extend phase-coherently across the entire wire geometry. The phase-coherence lengths are enhanced up to 5 µm when tuning the wires into the bulk gap, so as to single out topological transport. The nanowires exhibit distinct conductance oscillations, both as a function of the flux due to an axial magnetic field, and of a gate voltage. The observed h/e-periodic Aharonov-Bohm-type modulations indicate surface-mediated quasi-ballistic transport. Furthermore, an in-depth analysis of the scaling of the observed gate-dependent conductance oscillations reveals the topological nature of these surface states. To this end we combined numerical tight-binding calculations of the quantum magneto-conductance with simulations of the electrostatics, accounting for the gate-induced inhomogenous charge carrier densities around the wires. We find that helical transport prevails even for strongly inhomogeneous gating and is governed by flux-sensitive high-angular momentum surface states that extend around the entire wire circumference. arXiv:1708.07014v2 [cond-mat.mes-hall]

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Section: Introductionmentioning

confidence: 73%

Probing spin helical surface states in topological HgTe nanowires

et al. 2018

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“…Moreover, it was recently shown to have characteristics associated with topologically nontrivial band inversion [8] and that if formed as a 2D crystal it may exhibit topological insulator characteristics [9]. Topological insulator behavior is also well established [10][11][12][13] in Ag 2 Se and Ag 2 Te. However the Cu 2−x Te phase diagram includes structures not fully determined in all cases, and there are several phase transitions at high temperatures [14,15] as the Te lattice adapts to superionic motion of the Cu ions [16].…”

Section: Introductionmentioning

confidence: 98%

NMR study of vacancy and structure-induced changes in Cu2-xTe

Sirusi

Page

Uher

et al. 2017

Journal of Physics and Chemistry of Solids

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We report Cu and Te NMR measurements on Cu 2−x Te with x between 0.13 and 0.22. Aided by powder x-ray analysis and computed NMR quadrupole shifts, a structure change near x = 0.20 was found consistent with structures reported by Baranova, with best fits to the β-I structure for x = 0.22 and β-III for smaller x. NMR T 1 and Hall effect results demonstrate p-type electronic behavior with filling of simple hole pockets induced by increased numbers of vacancies for both phases. Furthermore the Cu and Te chemical shifts are large and negative, as observed in topologically inverted semiconductors, with a splitting into two distinct local environments for both Cu and Te sites in the x = 0.22 structure. Cu T 1 results show a rapid decrease of the energy barrier for initiation of Cu ion hopping to 0.12 eV for x = 0.22, considerably smaller than observed at higher temperatures, indicating a tail of relatively mobile Cu ions which may be of significance for potential device applications.

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“…Since the WAL effect is due to a two-dimensional surface state, only the normal component of magnetic (B) field, Bsinθ, contributes to the negative MC behavior, where θ is the angle of the magnetic field relative to the substrate. Thus, the MC curves obtained at different angles were merged into a single one when those were replotted against Bsinθ [9,29]. Figure 1c According to the Hikami-Larkin-Nagaoka (HLN) theory [28], the WAL effect in twodimensional (2D) limit can be expressed by…”

Section: Resultsmentioning

confidence: 99%

“…Thus, under an applied external magnetic field along the NR axis, the magneto-conductance of TI NR oscillates with magnetic flux threading the cross-sectional area of the NR, the so-called A-B oscillations in TI NR. The A-B oscillations provide an evidence for the TSS in TI NR [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Superconducting quantum interference devices made of Sb-doped Bi2Se3 topological insulator nanoribbons

Kim

Hou

et al. 2020

Current Applied Physics

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We report the fabrication and characterization of superconducting quantum interference devices (SQUIDs) made of Sb-doped Bi 2 Se 3 topological insulator (TI) nanoribbon (NR) contacted with PbIn superconducting electrodes. When an external magnetic field was applied along the NR axis, the TI NR exhibited periodic magneto-conductance oscillations, the so-called Aharonov-Bohm oscillations, owing to one-dimensional subbands. Below the superconducting transition temperature of PbIn electrodes, we observed supercurrent flow through TI NR-based SQUID. The critical current periodically modulates with a magnetic field perpendicular to the SQUID loop, revealing that the periodicity corresponds to the superconducting flux quantum. Our experimental observations can be useful to explore Majorana bound states (MBS) in TI NR, promising for developing topological quantum information devices.

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Quantum Electronic Transport of Topological Surface States in β-Ag₂Se Nanowire

Cited by 24 publications

References 59 publications

Probing spin helical surface states in topological HgTe nanowires

Probing spin helical surface states in topological HgTe nanowires

NMR study of vacancy and structure-induced changes in Cu2-xTe

Superconducting quantum interference devices made of Sb-doped Bi2Se3 topological insulator nanoribbons

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Quantum Electronic Transport of Topological Surface States in β-Ag2Se Nanowire

Cited by 24 publications

References 59 publications

Probing spin helical surface states in topological HgTe nanowires

Probing spin helical surface states in topological HgTe nanowires

NMR study of vacancy and structure-induced changes in Cu2-xTe

Superconducting quantum interference devices made of Sb-doped Bi2Se3 topological insulator nanoribbons

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Quantum Electronic Transport of Topological Surface States in β-Ag₂Se Nanowire