Electronic structure of (1e,1h) states of carbon nanotube quantum dots

E. N. Osika and B. Szafran
Phys. Rev. B 93, 165304 – Published 11 April 2016

Abstract

We provide an atomistic tight-binding description of a few carriers confined in ambipolar (np) double quantum dots defined in a semiconducting carbon nanotube. We focus our attention on the charge configuration in which Pauli blockade of the current flow is observed [F. Pei et al., Nat. Nanotechnol. 7, 630 (2012); E. A. Laird et al., Nat. Nanotechnol. 8, 565 (2013)] with a single excess electron in the n dot and a single hole in the p dot. We use the configuration interaction approach to determine the spin-valley structure of the states near the neutrality point and discuss its consequences for the interdot exchange interaction, the degeneracy of the energy spectrum, and the symmetry of the confined states. We calculate the transition energies lifting the Pauli blockade and analyze their dependence on the magnetic field vector. Furthermore, we introduce bending of the nanotube and demonstrate its influence on the transition energy spectra. The best qualitative agreement with the experimental data is observed for nanotubes deflected in the gated areas in which the carrier confinement is induced.

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  • Received 29 December 2015
  • Revised 7 March 2016

DOI:https://doi.org/10.1103/PhysRevB.93.165304

©2016 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

E. N. Osika1,2 and B. Szafran1

  • 1Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland
  • 2Institut de Ciéncies Fotóniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain

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Issue

Vol. 93, Iss. 16 — 15 April 2016

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