Tunneling spectroscopy of ultrathin insulating Cu 2N films, and single Co adatoms

T. Choi, C. D. Ruggiero, J. A. Gupta

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21 Scopus citations


Scanning tunneling microscopy is used to characterize the electronic structure of 1 ML films of c (2×2) NCu (100) (i.e., Cu2 N). By varying nitrogen coverage, a variety of morphologies are prepared, including (1) isolated ∼25 nm2 islands, (2) close-packed arrays of islands, and (3) quasicontinuous monolayer films. In all three regimes, the authors find that Cu2 N acts as an insulator, with a band gap that exceeds 4 eV. The insulating Cu2 N films are used to control the coupling of adsorbed Co atoms to the Cu(100) surface electron density. Tunneling spectroscopy of Co on Cu2 N reveals an unoccupied atomic resonance, Kondo effect, and spin-flip excitation. These features depend on binding site within the Cu2 N film, and are distinctly different than corresponding spectra for Co on Cu(100).

Original languageEnglish
Pages (from-to)887-890
Number of pages4
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Issue number2
StatePublished - 2009

Bibliographical note

Funding Information:
The authors thank A. J. Heinrich, C. F. Hirjibehedin, and A. F. Otte for helpful discussions concerning their recent results. They are grateful for support from NSF CAREER DMR-0645451.


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