Physical Review Research (Mar 2024)

Quantum dots on the InAs(110) cleavage surface created by atom manipulation

  • Van Dong Pham,
  • Yi Pan,
  • Steven C. Erwin,
  • Stefan Fölsch

DOI
https://doi.org/10.1103/PhysRevResearch.6.013269
Journal volume & issue
Vol. 6, no. 1
p. 013269

Abstract

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Cryogenic scanning tunneling microscopy was employed in combination with density-functional theory calculations to explore quantum dots made of In adatoms on the InAs(110) surface. Each adatom adsorbs at a surface site coordinated by one cation and two anions, and transfers one electron to the substrate, creating an attractive quantum well for electrons at the surface. We used the scanning-probe tip to assemble the positively charged adatoms into precisely defined quantum dots exhibiting a bound state roughly 0.1 eV below the Fermi level at an intrinsic linewidth of only ∼4 meV, as revealed by scanning tunneling spectroscopy. For quantum-dot dimers, we observed the emergence of a bonding and an antibonding state with even and odd wave-function character, respectively, demonstrating the capability to engineer quasimolecular electronic states. InAs(110) constitutes a promising platform in this respect because highly perfect surfaces can be readily prepared by cleavage and charged adatoms can be generated in situ by the scanning-probe tip.