Skipping orbits and enhanced resistivity in large-diameter InAs/GaSb antidot lattices

Eroms, Jonathan; Zitzlsperger, M; Weiss, Dieter; Smet, J. H.; Albrecht, C.; Fleischmann, Ragnar; Behet, M.; Boeck, J. De; Borghs, Gustaaf

doi:10.1103/physrevb.59.r7829

Cited by 19 publications

(25 citation statements)

References 14 publications

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“…2) effect is reproduced in our hard wall simulations (not shown), in contrast to hard wall simulations performed for square lattices [5]. In square lattices consisting of antidots with similar ratios d/a, simulations do not suggest the existence of type 2 -orbits, independent of the wall steepness [10]. Thus, the wall steepness seems less critical in hexagonal arrays, but becomes more relevant as d e /a increases.…”

Section: Interpretation and Discussioncontrasting

confidence: 71%

“…This type is present for all magnetic fields above 0.5T and covers a continuously increasing area in the Poincaré section as B is increased up to 2T. Such skipping orbit trajectories have already been discussed for square antidot lattices [10]. The second type are triangularly or rosette-type shaped trajectories that form quasi-closed figures by consecutive reflections at walls of adjacent antidots.…”

Section: Interpretation and Discussionmentioning

confidence: 58%

“…More recently, signatures of the famous fractal energy spectrum of such potentials, also known as the Hofstadter butterfly, have been observed [8,9]. A large fraction of these studies was performed on square [1,2,3,6,8,9,10] or rectangular [11] lattices, while only a few experiments on hexagonal lattices have been published [12,13,14,15]. For the majority of the effects, the lattice type is, in principle, irrelevant.…”

Section: Introductionmentioning

confidence: 99%

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Commensurability effects in hexagonal antidot lattices with large antidot diameters

Meckler

Heinzel

Cavanna³

et al. 2005

Phys. Rev. B

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The observation of a novel type of commensurability resonance in two-dimensional, hexagonal antidot lattices is reported. These resonances have a classical character and occur at magnetic fields above the resonance that corresponds to the cyclotron motion around a single antidot. The resonances are visible only for antidots with effective diameters larger than 50 % of the lattice constant. Simulations reveal that they originate from quasi-stable electron trajectories that bounce between three neighboring antidots. This interpretation is backed by the observation of large-period Aharonov-Bohm type oscillations at low temperatures.

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Section: Interpretation and Discussioncontrasting

confidence: 71%

Section: Interpretation and Discussionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 99%

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Commensurability effects in hexagonal antidot lattices with large antidot diameters

Meckler

Heinzel

Cavanna³

et al. 2005

Phys. Rev. B

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“…and of the energy spectrum consisting of magnetic subbands. For example, the oscillations of longitudinal magnetoresistance have been detected under the conditions where classical cyclotron radius 2R c envelopes an integer number of antidots or numerous reflections from one antidot occur 22,23 . It should be mentioned that the effects of randomly distributed impurities on collision broadening and transport scattering rate in 2D electron gas with periodical modulation, which consideration is of great importance for experimentators, have also been studied theoretically 24 .…”

mentioning

confidence: 99%

Quantum Hall effect in ap-type heterojunction with a lateral surface superlattice

Demikhovskiǐ

Khomitskiy

2003

Phys. Rev. B

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The quantization of Hall conductance in a p-type heterojunction with lateral surface quantum dot superlattice is investigated. The topological properties of the fourcomponent hole wavefunction are studied both in r-and k-spaces. New method of calculation of the Hall conductance in a 2D hole gas described by the Luttinger Hamiltonian and affected by lateral periodic potential is proposed, based on the investigation of fourcomponent wavefunction singularities in k-space. The deviations from the quantization rules for Hofstadter "butterfly" for electrons are found, and the explanation of this effect is proposed. For the case of strong periodic potential the mixing of magnetic subbands is taken into account, and the exchange of the Chern numbers between magnetic subands is discussed.

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“…Most prominently, a peak appears in the magnetoresistance when the diameter of the cyclotron orbit 2R c matches the lattice period a. Depending on the dot diameter and the mean free path, more features can be observed at lower (corresponding to larger orbits encircling more antidots) or higher fields (when the orbits bounce off the antidot walls several times [31]). If the specular reflection at the antidot boundary is replaced by Andreev reflection, the character of the orbits should change and different features should be observed.…”

Section: Andreev Reflection and Chaotic Motionmentioning

confidence: 96%

Transport in Nb-InAs structures: from phase coherence to the edge state regime

Eroms

Weiss

2007

Appl. Phys. A

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We investigated transport in Nb-InAs hybrid structures in perpendicular magnetic fields up to the quantum Hall regime. Due to the high contact quality of our samples, Andreev reflection dominates the transport properties in a range of experimental parameters. Our experiments were performed on periodic arrays of Nb filled stripes or antidots in an InAs-based 2DEG. According to geometry and field strength we observe the following effects: At low fields, up to a few flux quanta per unit cell, we find phase-coherent behavior, such as flux-periodic oscillations. At slightly higher fields, the Andreev reflection probability is determined by induced superconductivity in the 2DEG, which is gradually suppressed by an increasing magnetic field. In the arrays of Nb filled antidots we find that the commensurability peaks are suppressed since Andreev reflection restores regular motion in velocity space. Due to the high critical field of the Nb nanostructures, we can also enter the edge state regime, where we observe a pronounced increase of the amplitude of 1/B-periodic magnetoresistance oscillations. The latter can be traced to an enhanced backscattering of Andreevreflected edge channels, which contain both electrons and holes. When different material classes are combined in solid state physics, new and unexpected behavior is frequently observed. In this article we describe experiments on superconductor-semiconductor structures fabricated from the Nb-InAs material system. With semiconductors we typically associate properties such as tunable electron density and high carrier mobility, and effects such as the quantum Hall effect or ballistic transport [1,2], to name a few examples. Superconductors, on the other hand, are known for their perfect conductivity, phase coherence or the Josephson effect. If both materials are brought into contact, many new phenomena arise, which are based on Andreev reflection [3]. This process takes places at the boundary between a superconductor and a normal conductor (which can be a metal or a semiconductor). When an

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Skipping orbits and enhanced resistivity in large-diameter InAs/GaSb antidot lattices

Cited by 19 publications

References 14 publications

Commensurability effects in hexagonal antidot lattices with large antidot diameters

Commensurability effects in hexagonal antidot lattices with large antidot diameters

Quantum Hall effect in ap-type heterojunction with a lateral surface superlattice

Transport in Nb-InAs structures: from phase coherence to the edge state regime

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