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Title: Controlling orbital-selective Kondo effects in a single molecule through coordination chemistry

Iron(II) phthalocyanine (FePc) molecule causes novel Kondo effects derived from the unique electronic structure of multi-spins and multi-orbitals when attached to Au(111). Two unpaired electrons in the d{sub z}{sup 2} and the degenerate dπ orbitals are screened stepwise, resulting in spin and spin+orbital Kondo effects, respectively. We investigated the impact on the Kondo effects of the coordination of CO and NO molecules to the Fe{sup 2+} ion as chemical stimuli by using scanning tunneling microscopy (STM) and density functional theory calculations. The impacts of the two diatomic molecules are different from each other as a result of the different electronic configurations. The coordination of CO converts the spin state from triplet to singlet, and then the Kondo effects completely disappear. In contrast, an unpaired electron survives in the molecular orbital composed of Fe d{sub z}{sup 2} and NO 5σ and 2π* orbitals for the coordination of NO, causing a sharp Kondo resonance. The isotropic magnetic response of the peak indicates the origin is the spin Kondo effect. The diatomic molecules attached to the Fe{sup 2+} ion were easily detached by applying a pulsed voltage at the STM junction. These results demonstrate that the single molecule chemistry enables us to switchmore » and control the spin and the many-body quantum states reversibly.« less
Authors:
; ;  [1] ; ;  [2]
  1. Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)
  2. RIKEN, 2-1 Hirosawa, Saitama 351-0198 (Japan)
Publication Date:
OSTI Identifier:
22420000
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON MONOXIDE; CONTROL; DENSITY FUNCTIONAL METHOD; ELECTRIC POTENTIAL; ELECTRONIC STRUCTURE; IRON; IRON IONS; MOLECULAR ORBITAL METHOD; MOLECULES; NITRIC OXIDE; PHTHALOCYANINES; QUANTUM STATES; RESONANCE; SCANNING TUNNELING MICROSCOPY; SPIN; TRIPLETS