Electrostatic Interaction across a Single-Layer Carbon Shell

Abstract

Ions inside of fullerene molecules are model systems for the study of the electrostatic interaction across a single layer of carbon. For TbScN@C on h-BN/Ni(111), we observe with high-resolution X-ray photoelectron spectroscopy a splitting of the C 1s core level. The data may be explained quantitatively with density functional theory. The correlation of the C 1s eigenvalues and the Coulomb potential of the inside ions at the corresponding carbon sites indicates incomplete screening of the electric field due to the endohedral ions. The screening comprises anisotropic charge transfer to the carbon atoms and their polarization. This behavior is essential for the ordering of endohedral single-molecule magnets and is expected to occur in any single-layer material.

Endohedral metal-nitride cluster ordering in metallofullerene–NiII(OEP) complexes and crystals: a theoretical study

“…As both Ni(OEP) and EMF molecules have inhomogeneous charge distribution, electrostatic interactions may play an important role. This factor can be analyzed qualitatively with the help of electrostatic potential distribution 15 as shown in Fig. 3.…”

Temperature induced change of conformation of Sc2TbN@C80 on h-BN/Ni(111)

“…The photoemission data were recorded at a photon energy of 600 eV or He Iα (21.2 eV) [24]. The coverage was determined with a layer by layer growth model, with an electron mean free path of 1 nm and from the intensity ratio of the N 1s core levels of the molecule and h-BN [21]. The low energy electron diffraction (LEED) patterns were calibrated with the (0,1) spots of the h-BN/Ni(111) substrate [25].…”

“…Density functional theory (DFT) calculations were performed on the Sc 2 YN@C 80 endofullerene because it is chemically very similar to Sc 2 TbN@C 80 but easier to describe accurately [21]. The calculations on the isolated Sc 2 YN@C 80 cluster were performed with ORCA [26] and the calculations of Sc 2 YN@C 80 /h-BN/Ni(111) using Quantum ESPRESSO [27]; details are given in the supplemental material [25].…”

“…The orientation of the endohedral units may even be changed by magnetic fields [20]. On the other hand, the incomplete screening of the anisotropic electrostatic potential of the endohedral cluster [21] bears a handle for accessing the magnetisation of the endohedral clusters with electric fields.…”

Circular dichroism and angular deviation in x-ray absorption spectra of Dy2ScN@C80 single-molecule magnets on h−BN/Greber1, Seitsonen2, Hemmi3 et al. 2019Phys. Rev. MaterialsSelf Cite13080View full textAdd to dashboardCite

“…While we understand why Dy 2 ScN@C 80 is the most stable single-molecule magnet in the Dy n Sc 3−n N@C 80 , n ∈ {1, 2, 3} series [13], the understanding of why the endohedral unit of Dy 3 N@C 80 on Cu(111) [14], or Dy 2 ScN@C 80 on Rh(111) [2], show a tendency to orient parallel to the surface, even at room temperature [14], was lacking. Likely, it is related to the nonisotropic electric field outside the C 80 cage as it may be inferred from C 1s x-ray photoelectron spectroscopy (XPS) [15]. A second way to address the orientation of the endohedral unit is magnetic torque [16].…”