Nanomechanical characterization of quantum interference in a topological insulator nanowire

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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Many-impurity scattering on the surface of a topological insulator

Scientific Reports ◽

10.1038/s41598-021-84801-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

José Luis Hernando ◽

Yuriko Baba ◽

Elena Díaz ◽

Francisco Domínguez-Adame

Keyword(s):

Green’S Function ◽

Green's Function ◽

Topological Insulator ◽

Disordered Systems ◽

Spectral Properties ◽

Random Distribution ◽

Surface States ◽

Impurity Scattering ◽

Self Consistent ◽

The Impact

AbstractWe theoretically address the impact of a random distribution of non-magnetic impurities on the electron states formed at the surface of a topological insulator. The interaction of electrons with the impurities is accounted for by a separable pseudo-potential method that allows us to obtain closed expressions for the density of states. Spectral properties of surface states are assessed by means of the Green’s function averaged over disorder realisations. For comparison purposes, the configurationally averaged Green’s function is calculated by means of two different self-consistent methods, namely the self-consistent Born approximation (SCBA) and the coherent potential approximation (CPA). The latter is often regarded as the best single-site theory for the study of the spectral properties of disordered systems. However, although a large number of works employ the SCBA for the analysis of many-impurity scattering on the surface of a topological insulator, CPA studies of the same problem are scarce in the literature. In this work, we find that the SCBA overestimates the impact of the random distribution of impurities on the spectral properties of surface states compared to the CPA predictions. The difference is more pronounced when increasing the magnitude of the disorder.

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Induced unconventional superconductivity on the surface states of Bi2Te3 topological insulator

Nature Communications ◽

10.1038/s41467-017-02069-z ◽

2017 ◽

Vol 8 (1) ◽

Cited By ~ 22

Author(s):

Sophie Charpentier ◽

Luca Galletti ◽

Gunta Kunakova ◽

Riccardo Arpaia ◽

Yuxin Song ◽

...

Keyword(s):

Magnetic Field ◽

Topological Insulator ◽

Quantum Interference ◽

Order Parameter ◽

Thermal Strain ◽

Surface States ◽

Field Pattern ◽

Key Factors ◽

Ordered Phases ◽

Simultaneous Existence

Abstract Topological superconductivity is central to a variety of novel phenomena involving the interplay between topologically ordered phases and broken-symmetry states. The key ingredient is an unconventional order parameter, with an orbital component containing a chiral p x + ip y wave term. Here we present phase-sensitive measurements, based on the quantum interference in nanoscale Josephson junctions, realized by using Bi2Te3 topological insulator. We demonstrate that the induced superconductivity is unconventional and consistent with a sign-changing order parameter, such as a chiral p x + ip y component. The magnetic field pattern of the junctions shows a dip at zero externally applied magnetic field, which is an incontrovertible signature of the simultaneous existence of 0 and π coupling within the junction, inherent to a non trivial order parameter phase. The nano-textured morphology of the Bi2Te3 flakes, and the dramatic role played by thermal strain are the surprising key factors for the display of an unconventional induced order parameter.

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QUANTUM WAVEGUIDE THEORY FOR TRIPLY CONNECTED AHARONOV–BOHM RINGS

International Journal of Modern Physics B ◽

10.1142/s0217979296000295 ◽

1996 ◽

Vol 10 (06) ◽

pp. 701-712 ◽

Cited By ~ 6

Author(s):

CHANG-MO RYU ◽

SAM YOUNG CHO ◽

MINCHEOL SHIN ◽

KYOUNG WAN PARK ◽

SEONGJAE LEE ◽

...

Keyword(s):

Magnetic Flux ◽

Wave Vector ◽

Quantum Interference ◽

Transmission Probability ◽

Interference Effects ◽

Quantum Waveguide ◽

One Dimensional ◽

Waveguide Theory ◽

Aharonov Bohm ◽

Transmission And Reflection

Quantum interference effects for a mesoscopic loop with three leads are investigated by using a one-dimensional quantum waveguide theory. The transmission and reflection probabilities are analytically obtained in terms of the magnetic flux, arm length, and wave vector. Oscillation of the magnetoconductance is explicitly demonstrated. Magnetoconductance is found to be sharply peaked for certain localized values of flux and kl. In addition, it is noticed that the periodicity of the transmission probability with respect to kl depends more sensitively on the lead position, compared to the case of the two-lead loop.

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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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QUANTUM WAVEGUIDE THEORY FOR A MESOSCOPIC RING SUBJECT TO THE AHARONOV–CASHER EFFECT

Modern Physics Letters B ◽

10.1142/s0217984996000456 ◽

1996 ◽

Vol 10 (09) ◽

pp. 401-407 ◽

Cited By ~ 3

Author(s):

CHANG-MO RYU ◽

TAESEUNG CHOI ◽

CHUL KOO KIM ◽

KYUN NAHM

Keyword(s):

Gauge Theory ◽

Quantum Interference ◽

Transmission Probability ◽

Quantum Waveguide ◽

One Dimensional ◽

Device Application ◽

Waveguide Theory ◽

Mesoscopic Ring ◽

Aharonov Bohm

A one-dimensional quantum waveguide theory is developed for a mesoscopic ring subject to the Aharonov–Casher(AC) effect based on the SU (2) spin gauge theory. The quantum interference by the AC effect is found to be equivalent to that by the Aharonov–Bohm(AB) effect. This indicates that AC effect can be utilized for device application in a very similar manner to the AB effect. The transmission probability induced by the AC effect is shown to be identical for the spin up and down components.

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Quantum interference of surface states in bismuth nanowires probed by the Aharonov-Bohm oscillatory behavior of the magnetoresistance

Physical Review B ◽

10.1103/physrevb.77.075332 ◽

2008 ◽

Vol 77 (7) ◽

Cited By ~ 27

Author(s):

A. Nikolaeva ◽

D. Gitsu ◽

L. Konopko ◽

M. J. Graf ◽

T. E. Huber

Keyword(s):

Quantum Interference ◽

Surface States ◽

Oscillatory Behavior ◽

Bismuth Nanowires ◽

Aharonov Bohm

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Glide symmetry protected higher-order topological insulators from semimetals with butterfly-like nodal lines

npj Computational Materials ◽

10.1038/s41524-021-00672-9 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Xiaoting Zhou ◽

Chuang-Han Hsu ◽

Cheng-Yi Huang ◽

Mikel Iraola ◽

Juan L. Mañes ◽

...

Keyword(s):

Topological Insulator ◽

Topological Insulators ◽

Surface States ◽

Nodal Line ◽

Higher Order ◽

Dirac Fermion ◽

Space Groups ◽

Nodal Lines ◽

Topological Semimetals ◽

Symmetry Protected

AbstractMost topological insulators (TIs) discovered today in spinful systems can be transformed from topological semimetals (TSMs) with vanishing bulk gap via introducing the spin-orbit coupling (SOC), which manifests the intrinsic links between the gapped topological insulator phases and the gapless TSMs. Recently, we have discovered a family of TSMs in time-reversal invariant spinless systems, which host butterfly-like nodal-lines (NLs) consisting of a pair of identical concentric intersecting coplanar ellipses (CICE). In this Communication, we unveil the intrinsic link between this exotic class of nodal-line semimetals (NLSMs) and a $${{\mathbb{Z}}}_{4}$$ Z 4 = 2 topological crystalline insulator (TCI), by including substantial SOC. We demonstrate that in three space groups (i.e., Pbam (No.55), P4/mbm (No.127), and P42/mbc (No.135)), the TCI supports a fourfold Dirac fermion on the (001) surface protected by two glide symmetries, which originates from the intertwined drumhead surface states of the CICE NLs. The higher order topology is further demonstrated by the emergence of one-dimensional helical hinge states, indicating the discovery of a higher order topological insulator protected by a glide symmetry.

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