Frontier Orbital Degeneracy: A New Concept for Tailoring the Magnetic State in Organic Semiconductor Adsorbates
Journal Article
·
· Journal of Physical Chemistry. C
- Univ. of Arizona, Tucson, AZ (United States)
- Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
- Univ. of Arizona, Tucson, AZ (United States); Friedrich Schiller Univ., Jena (Germany)
- Friedrich Schiller Univ., Jena (Germany)
Kondo resonances in molecular adsorbates are an important building block for applications in the field of molecular spintronics. Here, we introduce the novel concept of using frontier orbital degeneracy for tailoring the magnetic state, which is demonstrated for the case of the organic semiconductor 1,4,5,8,9,11-Hexaazatriphenylenehexacarbonitrile (HATCN, C18N12) on Ag(111). Low-temperature scanning tunneling microscopy/spectroscopy (LT-STM/STS) measurements reveal the existence of two types of adsorbed HATCN molecules with distinctly different appearances and magnetic states, as evident from the presence or absence of an Abrikosov-Suhl-Kondo resonance. Our DFT results show that HATCN on Ag(111) supports two almost isoenergetic states, both with one excess electron transferred from the Ag surface, but with magnetic moments of either 0 or 0.65 μB. Therefore, even though all molecules undergo charge transfer of one electron from the Ag substrate, they exist in two different molecular magnetic states that resemble a free doublet or an entangled spin state. We explain how the origin of this behavior lies in the twofold degeneracy of the lowest unoccupied molecular orbitals of gas phase HATCN, lifted upon adsorption and charge-transfer from Ag(111). In conclusion, our combined STM and DFT study introduces a new pathway to tailoring the magnetic state of molecular adsorbates on surfaces, with significant potential for spintronics and quantum information science.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 2242391
- Report Number(s):
- BNL--225080-2023-JAAM
- Journal Information:
- Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 48 Vol. 127; ISSN 1932-7447
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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