论文部分内容阅读
Layered compounds play pivotal roles as precursors for producing 2D materials through mechanical exfoliation(micro-mechanical cleavage) or chemical approaches. Therefore, searching for layered compounds with sharp anisotropic chemical bonding and properties becomes emergent. In this work, the stability, electronic structure, elastic properties, and lattice dynamics of YB_2C_2 were investigated. Strong anisotropy in elastic properties is revealed, i.e., high Young’s modulus in a-b plane but low Young’s modulus in c direction. The maximum to minimum Young’s modulus ratio is 2.41 and 2.45 for YB_2C_2 with P42/mmc and P4/mbm symmetry, respectively. The most likely systems for shear sliding or microdelaminating are(001)[100] and(001)[010]. The anisotropic elastic properties are underpinned by the anisotropic chemical bonding, i.e., strong bonding within the B_2C_2 nets and weak bonding between Y atom layers and B_2C_2 nets. YB_2C_2 is electrically conductive and the contributions to the electrical conductivity are from delocalized Y 4de_g as well as B _2p_z and _ pzelectrons. The layered crystal structure, sharp anisotropic mechanical properties, and metallic conductivity endorse YB_2C_2 promising as a precursor for new 2D B_2C_2 nets.
Layered compounds play pivotal roles as precursors for producing 2D materials through mechanical exfoliation (micro-mechanical cleavage) or chemical approaches. Thus, searching for layered compounds with sharp anisotropic chemical bonding and properties emergent. In this work, the stability, electronic structure, Strong anisotropy in elastic properties is revealed, ie, high Young’s modulus in ab plane but low Young’s modulus in c direction. The maximum to minimum Young’s modulus ratio is 2.41 and 2.45 for YB_2C_2 with P42 / mmc and P4 / mbm symmetry, respectively. The most likely systems for shear sliding or microdelaminating are (001) [100] and (001) [010]. The anisotropic elastic properties are underpinned by the anisotropic chemical bonding, ie, strong bonding within the B_2C_2 nets and weak bonding between Y atoms layers and B_2C_2 nets. YB_2C_2 is electrically conductive and the contributions to the ele The layered crystal structure, sharp anisotropic mechanical properties, and metallic conductivity endorse YB_2C_2 promising as a precursor for new 2D B_2C_2 nets.