Corner and side localization of electrons in irregular hexagonal semiconductor shells

Sitek, Anna; Torres, Miguel Urbaneja; Manolescu, Andrei

doi:10.1088/1361-6528/ab37a1

Cited by 8 publications

(3 citation statements)

References 43 publications

(85 reference statements)

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“…5. This is in agreement with single-band self-consistent calculations [18,58], as expected from the nearly pure EL character of conduction subbands.…”

Section: B N-dopingsupporting

confidence: 91%

Band structure of n- and p-doped core-shell nanowires

Vezzosi,

Bertoni,

Goldoni

2022

Preprint

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We investigate the electronic band structure of modulation-doped GaAs/AlGaAs core-shell nanowires for both n-and p-doping. We developed an 8-band Burt-Foreman k • p Hamiltonian approach to describe coupled conduction and valence bands in heterostructured nanowires of arbitrary composition, growth directions, and doping. Coulomb interactions with the electron/hole gas are taken into account within a mean-field self-consistent approach. We map the ensuing multiband envelope function and Poisson equations to optimized, non-uniform real-space grids by the finite element method. Self-consistent charge density, single-particle subbands, density of states and absorption spectra are obtained at different doping regimes. For n-doped samples, the large restructuring of the electron gas for increasing doping results in the formation of quasi-1D electron channels at the core/shell interface. Strong heavy-hole/light-hole coupling of hole state leads to non parabolic dispersions with mass inversion, similarly to planar structures, which persist at large dopings, giving rise to direct LH and indirect HH gaps. In p-doped samples the hole gas forms an almost isotropic, ring-like cloud for a large range of doping. Here, as a result of the increasing localization, HH and LH states uncouple, and mass inversion takes place at a threshold density. Similar evolution is obtained at fixed doping as a function of temperature. We show that signatures of the evolution of band structure can be singled out in the anisotropy of linearly polarized optical absorption.

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“…5. This is in agreement with single-band self-consistent calculations [18,58], as expected from the nearly pure EL character of conduction subbands.…”

Section: B N-dopingsupporting

confidence: 91%

Band structure of n- and p-doped core-shell nanowires

Vezzosi,

Bertoni,

Goldoni

2022

Preprint

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“…The corner and side states are energetically separated by a gap interval that depends on the geometry and on the aspect ratio of the polygon. It increases with decreasing the shell thickness or the number of corners, and hence, in such a structure the subspace of corner states is potentially robust to many types of perturbations [53].…”

Section: Resultsmentioning

confidence: 99%

Electromagnetic field emitted by core-shell semiconductor nanowires driven by an alternating current

Torres,

Klausen,

Sitek

et al. 2019

Preprint

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We consider tubular nanowires with polygonal cross-section, whose geometry has important implications for the electron localization and separates the lowest energy groups into two sets of corner and side-localized states. The presence of an external magnetic field transversal to the nanowires imposes an additional localization mechanism, the electrons being pushed to the sides relative to the direction of the field. This has important implications on the current density, as it creates current loops induced by the Lorentz force. We calculate numerically the electromagnetic field radiated by hexagonal, square, and triangular nanowires. We demonstrate that, because of the aforementioned localization properties, the radiated field has an anisotropic behavior that can reproduce the internal geometry of the nanowire. Consequently, core-shell nanowires made of semiconductor materials, driven by an alternating current, may act as an anisotropic emitter nanoantenna, at least in the near-field domain.

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“…In particular, core-shell nanowires give rise to additional quantum effects since mobile two-dimensional electron gases (2DEGs) can form at the semiconductor-semiconductor heterojunction interface [8,9,10,11,12,13]. To fully harness the electronic properties of these systems, a wide range of material properties (such as doping density, bandgap alignment, geometry, and structural composition) may be altered to achieve spontaneous electron gas formation [14,15,16]. While the resulting parameter space is immense, theory and predictive modeling provide a guided path for determining which combination of material properties/parameters best optimizes performance of these novel nanosystems.…”

Section: Introductionmentioning

confidence: 99%

HADOKEN: An open-source software package for predicting electron confinement effects in various nanowire geometries and configurations

2022

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We present an open-source software package, HADOKEN (High-level Algorithms to Design, Optimize, and Keep Electrons in Nanowires), for predicting electron confinement/localization effects in nanowires with various geometries, arbitrary number of concentric shell layers, doping densities, and external boundary conditions. The HADOKEN code is written in the MATLAB programming environments to aid in its readability and general accessibility to both users and practitioners. We provide several examples and outputs on a variety of different nanowire geometries, boundary conditions, and doping densities to demonstrate the capabilities of the HADOKEN software package. As such, the use of this predictive and versatile tool by both experimentalists and theorists could lead to further advances in both understanding and tailoring electron confinement effects in these nanosystems.

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Corner and side localization of electrons in irregular hexagonal semiconductor shells

Cited by 8 publications

References 43 publications

Band structure of n- and p-doped core-shell nanowires

Band structure of n- and p-doped core-shell nanowires

Electromagnetic field emitted by core-shell semiconductor nanowires driven by an alternating current

HADOKEN: An open-source software package for predicting electron confinement effects in various nanowire geometries and configurations

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