Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan.
Published: September 2022
AI Article Synopsis
Article Abstract
Bilayer graphene (BLG) has a two-dimensional (2D) interlayer nanospace that can be used to intercalate molecules and ions, resulting in a significant change of its electronic and magnetic properties. Intercalation of BLG with different materials, such as FeCl, MoCl, Li ions, and Ca ions, has been demonstrated. However, little is known about how the twist angle of the BLG host affects intercalation. Here, by using artificially stacked BLG with controlled twist angles, we systematically investigated the twist angle dependence of intercalation of metal chlorides. We discovered that BLG with high twist angles of >15° is more favorable for intercalation than BLG with low twist angles. Density functional theory calculations suggested that the weaker interlayer coupling in high twist angle BLG is the key for effective intercalation. Scanning transmission electron microscope observations revealed that co-intercalation of AlCl and CuCl molecules into BLG gives various 2D structures in the confined interlayer nanospace. Moreover, before intercalation we observed a significantly lower sheet resistance in BLG with high twist angles (281 ± 98 Ω/□) than that in AB stacked BLG (580 ± 124 Ω/□). Intercalation further decreased the sheet resistance, reaching values as low as 48 Ω/□, which is the lowest value reported so far for BLG. This work provides a twist angle-dependent phenomenon, in which enhanced intercalation and drastic changes of the electrical properties can be realized by controlling the stacking angle of adjacent graphene layers.
Thermodynamic theory suggests that the obvious mechanical behavior caused by temperature and interlayer angle will affect the physical properties of materials, such as mechanical properties and transportation behavior, and it is different from the behavior in three-dimensional bulk materials. We observe an abnormal physical effect of bilayer graphene/hexagonal boron nitride (G/BN)-carbon nanotube (CNT) heterostructures, with a normalized out-of-plane deformation and normalized bond angle percentage to almost several times higher those of pristine G/BN heterostructures (without CNT) at 700-800 K. Our combined finite element theory and molecular dynamics simulations confirmed that the combination of CNT and interlayer angle diverted and bridged the propagating crack and provided a stable crack propagation path and crack tip opening displacement, resulting in the stress fields to be controlled around the CNT at high temperature.
Taking into account phase-polarization interactions is crucial for the formation of spatially structured laser beams. The effects that arise in this context can lead to the modulation of individual field components and the transformation of the overall light field. In this study, we investigate the impact of phase and polarization distributions with radial dependencies in polar coordinates on the longitudinal component of laser beams passing through a transmissive spatial light modulator (SLM) based on twisted nematic liquid crystals.
Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA and Quantum Materials and Sensing Institute, Northeastern University, Burlington, Massachusetts 01803, USA.
In contrast to the Dirac-cone materials in which the low-energy spectrum features a pseudospin-1/2 structure, Lieb and Dice lattices both host triply degenerate low-energy excitations. Here, we discuss moiré structures involving twisted bilayers of these lattices, which are shown to exhibit a tunable number of isolated flat bands near the Fermi level due to the bipartite nature of their structures. These flat bands remain isolated from the high-energy bands even in the presence of small higher-order terms and chiral-symmetry-breaking interlayer tunneling.
The title compound, CHClNO, is significantly distorted from planarity, with a twist angle between the planes through the hy-droxy-benzene and acetamide groups being 23.5 (2)°. This conformation is supported by intra-molecular C-H⋯O and N-H⋯Cl contacts.
The mol-ecular structure of the title compound, CHNO reveals non-co-planarity between the central formamidine backbone and each of the outer meth-oxy- and -propyl- substituted benzene rings with dihedral angles of 7.88 (15) and 81.17 (15)°, respectively, indicating significant twists in the mol-ecule.
