Interaction-Driven Giant Orbital Magnetic Moments in Carbon Nanotubes

Joshua O. Island, Marvin Ostermann, Lee Aspitarte, Ethan D. Minot, Daniele Varsano, Elisa Molinari, Massimo Rontani, and Gary A. Steele
Phys. Rev. Lett. 121, 127704 – Published 20 September 2018
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Abstract

Carbon nanotubes continue to be model systems for studies of confinement and interactions. This is particularly true in the case of so-called “ultraclean” carbon nanotube devices offering the study of quantum dots with extremely low disorder. The quality of such systems, however, has increasingly revealed glaring discrepancies between experiment and theory. Here, we address the outstanding anomaly of exceptionally large orbital magnetic moments in carbon nanotube quantum dots. We perform low temperature magnetotransport measurements of the orbital magnetic moment and find it is up to 7 times larger than expected from the conventional semiclassical model. Moreover, the magnitude of the magnetic moment monotonically drops with the addition of each electron to the quantum dot directly contradicting the widely accepted shell filling picture of single-particle levels. We carry out quasiparticle calculations, both from first principles and within the effective-mass approximation, and find the giant magnetic moments can only be captured by considering a self-energy correction to the electronic band structure due to electron-electron interactions.

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  • Received 12 January 2018

DOI:https://doi.org/10.1103/PhysRevLett.121.127704

© 2018 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Joshua O. Island1,*, Marvin Ostermann1, Lee Aspitarte2, Ethan D. Minot2, Daniele Varsano3, Elisa Molinari3,4, Massimo Rontani3,†, and Gary A. Steele1

  • 1Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands
  • 2Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA
  • 3CNR-NANO, Via Campi 213a, 41125 Modena, Italy
  • 4Dipartimento di Scienze Fisiche, Informatiche e Matematiche (FIM), Università degli Studi di Modena e Reggio Emilia, 41125 Modena, Italy

  • *jisland@physics.ucsb.edu Present address: Department of Physics, University of California, Santa Barbara, California 93106, USA.
  • massimo.rontani@nano.cnr.it

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Issue

Vol. 121, Iss. 12 — 21 September 2018

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