The Aharonov-Bohm oscillation in the BiSbTe3 topological insulator macroflake

AbstractWe study coherent spin transport through helical edge states of topological insulator tunnel-coupled to metallic leads. We demonstrate that unpolarized incoming electron beam acquires finite polarization after transmission through such a setup provided that edges contain at least one magnetic impurity. The finite polarization appears even in the fully classical regime and is therefore robust to dephasing. There is also a quantum magnetic field-tunable contribution to the polarization, which shows sharp identical Aharonov-Bohm resonances as a function of magnetic flux—with the period hc/2e—and survives at relatively high temperature. We demonstrate that this tunneling interferometer can be described in terms of ensemble of flux-tunable qubits giving equal contributions to conductance and spin polarization. The number of active qubits participating in the charge and spin transport is given by the ratio of the temperature and the level spacing. The interferometer can effectively operate at high temperature and can be used for quantum calculations. In particular, the ensemble of qubits can be described by a single Hadamard operator. The obtained results open wide avenue for applications in the area of quantum computing.

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Nanomechanical characterization of quantum interference in a topological insulator nanowire

Nature Communications ◽

10.1038/s41467-019-12560-4 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 5

Author(s):

Minjin Kim ◽

Jihwan Kim ◽

Yasen Hou ◽

Dong Yu ◽

Yong-Joo Doh ◽

...

Keyword(s):

Resonant Frequency ◽

Topological Insulator ◽

Quantum Interference ◽

Mechanical Vibration ◽

Surface States ◽

Impurity Scattering ◽

Dirac Fermion ◽

One Dimensional ◽

Aharonov Bohm

Abstract Aharonov–Bohm conductance oscillations emerge as a result of gapless surface states in topological insulator nanowires. This quantum interference accompanies a change in the number of transverse one-dimensional modes in transport, and the density of states of such nanowires is also expected to show Aharonov–Bohm oscillations. Here, we demonstrate a novel characterization of topological phase in Bi2Se3 nanowire via nanomechanical resonance measurements. The nanowire is configured as an electromechanical resonator such that its mechanical vibration is associated with its quantum capacitance. In this way, the number of one-dimensional transverse modes is reflected in the resonant frequency, thereby revealing Aharonov–Bohm oscillations. Simultaneous measurements of DC conductance and mechanical resonant frequency shifts show the expected oscillations, and our model based on the gapless Dirac fermion with impurity scattering explains the observed quantum oscillations successfully. Our results suggest that the nanomechanical technique would be applicable to a variety of Dirac materials.

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Anomalous Aharonov-Bohm Conductance Oscillations from Topological Insulator Surface States

Physical Review Letters ◽

10.1103/physrevlett.105.206601 ◽

2010 ◽

Vol 105 (20) ◽

Cited By ~ 109

Author(s):

Yi Zhang ◽

Ashvin Vishwanath

Keyword(s):

Topological Insulator ◽

Surface States ◽

Insulator Surface ◽

Aharonov Bohm

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NUMERICAL STUDY OF TRANSPORT PROPERTIES IN TOPOLOGICAL INSULATOR QUANTUM DOTS UNDER MAGNETIC FIELD

Modern Physics Letters B ◽

10.1142/s0217984913501042 ◽

2013 ◽

Vol 27 (14) ◽

pp. 1350104 ◽

Cited By ~ 4

Author(s):

SHENG-NAN ZHANG ◽

HUA JIANG ◽

HAIWEN LIU

Keyword(s):

Magnetic Field ◽

Quantum Dots ◽

Transport Properties ◽

Topological Insulator ◽

Numerical Study ◽

Spin Polarized ◽

Full Band ◽

Spin Degeneracy ◽

Aharonov Bohm ◽

The Magnetic Field

In this paper, we investigate the transport properties of HgTe / CdTe -based topological insulator quantum dots (TIQDs) under magnetic field. Both disk and square shaped TIQDs are considered and the magneto-conductance are calculated numerically for various magnetic field strength. The magnetic field lifts the spin degeneracy, leading to spin polarized current at given Fermi energy. Meanwhile, the magneto-conductance demonstrates the Aharonov–Bohm (AB) oscillation with a period of one flux quantum [Formula: see text]. Numerical results for AB oscillation features indicate the mismatch between electron (e) and hole (h) doping conditions, which can be attributed to the e–h asymmetry in the full band Hamiltonian. Further, interference effect emerges around bulk and edge energy degenerate points, subsequently suppressing the magneto-conductance in both shaped systems. All these physical characteristics are qualitatively consistent for disk and square shaped TIQDs due to the topological nature of edge modes.

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