Addition/Correction Cite This: J. Phys. Chem. C 2018, 122, 29080−29080
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Correction to Temperature‑, Light‑, and Soft X‑ray-Induced Spin Crossover in a Single Layer of FeII-Pyrazolylborate Molecules in Direct Contact with Gold Kaushik Bairagi, Amandine Bellec,* Cynthia Fourmental, Yongfeng Tong, Olga Iasco, Jérôme Lagoute, Cyril Chacon, Yann Girard, Sylvie Rousset, Fadi Choueikani, Edwige Otero, Philippe Ohresser, Philippe Sainctavit, Marie-Laure Boillot, Talal Mallah, and Vincent Repain J. Phys. Chem. C 2018, 122 (1), 727−731. DOI: 10.1021/acs.jpcc.7b11874 coverage of 0.48 ± 0.06 ML (average on 8 areas at different positions on the sample). As the diffusing molecules, corresponding to the stripes in between the islands in the STM image, are ignored, the coverage might be slightly underestimated. The same sample has been transferred to the DEIMOS beamline within a few hours under UHV (base pressure: 7.10−9 mbar) and measured at the L2,3-edge of Fe. The spectra at room temperature (Figure 1b) present an edge-jump of 1.1 ± 0.1%. For the sample presented in the main text, the edge jump was 3.6%, which therefore corresponds to a coverage of 1.57 ± 0.25 ML which is in rather good agreement with the calibration of ref 3. Thus, for the results presented in the main text, the proportion of molecules in the second layer cannot be neglected. Especially, the proportion of molecules in high spin state given in the main text corresponds to a global measurement over the two molecular layers knowing that the spin state and the switching properties of the molecules are most probably different between the ones in the first layer in contact with gold and the ones in the second layer.
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n the main text, the coverage was estimated as discussed in the Supporting Information (SI) to be less than a monolayer. Complementary experiments detailed below indicate that in fact the molecular coverage is 1.57 ± 0.25 ML. The calibration of the molecular coverage is a delicate task, and as discussed in the SI we tried by several means to evaluate it. We also compared the edge jump of our sample to a 130 nm sample as described in ref 1. Nonetheless, in the case of molecular thicknesses inferior to the escape length of the electrons, the background due to the substrate (here Au(111)) must be taken into account and the edge jump cannot be compared to a thick molecular film.2 We improved our calibration by first measuring our sample by scanning tunneling microscopy (STM) at 5 K and then transferring the sample in a ultrahigh vacuum (UHV) suitcase to the synchrotron beamline for X-ray absorption spectroscopy (XAS) measurements. Indeed, we prepared a sample of FeII((3,5-(CH3)2Pz)3BH)2 molecules sublimated (from a homemade Knudsen cell as described in the main text) on a Au(111) single crystal (prepared by standard sputtering and annealing procedure as described in the main text). A typical STM topography is presented in Figure 1a where molecular islands are observed with some molecules in second layer. The coverage is determined by measuring the area of the molecular islands taking into account the first and the second molecular layers with respect to the image area. We thus measured a
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(1) Warner, B.; Oberg, J. C.; Gill, T. G.; El Hallak, F.; Hirjibehedin, C. F.; Serri, M.; Heutz, S.; Arrio, M.-A.; Sainctavit, P.; Mannini, M.; et al. Temperature- and Light-Induced Spin Crossover Observed by X-ray Spectroscopy on Isolated Fe(II) Complexes on Gold. J. Phys. Chem. Lett. 2013, 4, 1546−1552. (2) Kuch, W.; Bernien, M. Controlling the magnetism of adsorbed metal-organic molecules. J. Phys.: Condens. Matter 2017, 29, 023001. (3) Gopakumar, T. G.; Bernien, M.; Naggert, H.; Matino, F.; Hermanns, C. F.; Bannwarth, A.; Mühlenberend, S.; Krüger, A.; Krüger, D.; Nickel, F.; et al. Spin-Crossover Complex on Au(111): Structural and Electronic Differences Between Mono- and Multilayers. Chem. - Eur. J. 2013, 19, 15702−15709.
Figure 1. Calibration of the molecular coverage on Au(111). (a) 1 × 1 μm2 STM topography of FeII((3,5-(CH3)2Pz)3BH)2 on Au(111) (bias voltage, −2 V; tunneling current, 50 pA; temperature, 5 K). (b) Averaged XAS spectrum recorded on the same sample at room temperature (the average is realized on 12 spectra: 3 are taken in circular right (CR) polarization under a magnetic field (H) of 0.1 T, 3 in circular left (CL) polarization under H = 0.1 T, 3 in CR polarization under H = −0.1 T, and 3 in CL polarization under H = −0.1 T). © 2018 American Chemical Society
REFERENCES
Published: December 12, 2018 29080
DOI: 10.1021/acs.jpcc.8b11550 J. Phys. Chem. C 2018, 122, 29080−29080
