Fig. 1: Schematic diagrams of monolayer, bilayer, and trilayer qHP C60; the differential charge density of the AB’A’ structure and the relative energies of 6 trilayer stacking configurations.
From: Cluster sliding ferroelectricity in trilayer Quasi-Hexagonal C60
a (left) The structural model of monolayer qHP C60. The blue and yellow pentagons are used to highlight C60 clusters in two different orientations. (right) A simplified illustration of the qHP C60 monolayer, where the blue and yellow spheres represent two different orientations of the C60. Bilayer qHP C60 in the b AB and c AB’ stacking configuration, with the inversion center labeled by the red star. d Trilayer C60 with AB’A’ stacking configuration. e The isosurface plot (with isosurface value of\(\,\pm 6.5\times {10}^{-5}\,e/{{\rm{Bohr}}}^{3}\)) of the differential charge density of the AB’A’ structure, where yellow and green isosurfaces indicate electron accumulation and depletion due to non-centrosymmetric layer stacking. f The relative energies of 6 stacking configurations and the out-of-plane polarization of the polar structure.
