Using first-principles calculations in the generalized gradient approximation plus on-site Coulomb interaction(GGA+U) scheme, the effects of internal structural parameters x and U on the electronic structure of YbB6 a...Using first-principles calculations in the generalized gradient approximation plus on-site Coulomb interaction(GGA+U) scheme, the effects of internal structural parameters x and U on the electronic structure of YbB6 are investigated. The results show that the band gap of YbB6 increases with x increasing, and does not change with U. It not only illustrates the influence of internal structural parameter x on band gap, but also explains the discrepancy between the previous experimental result and the theoretical prediction. In addition, the electronic structure and density of states reveal that there exist the interactions between B atoms in different cages, and that a small band gap can form around the Fermi level(EF). The present work plays a leading role in ascertaining the relation between crystal structure and electronic property for the further analysis of its topological properties.展开更多
基金Project supported by the Special Project of Department of Education of Shannxi Province,China(Grant No.18JK0710)the Natural Science Foundation of Shannxi Province,China(Grant No.2019JQ-105)
文摘Using first-principles calculations in the generalized gradient approximation plus on-site Coulomb interaction(GGA+U) scheme, the effects of internal structural parameters x and U on the electronic structure of YbB6 are investigated. The results show that the band gap of YbB6 increases with x increasing, and does not change with U. It not only illustrates the influence of internal structural parameter x on band gap, but also explains the discrepancy between the previous experimental result and the theoretical prediction. In addition, the electronic structure and density of states reveal that there exist the interactions between B atoms in different cages, and that a small band gap can form around the Fermi level(EF). The present work plays a leading role in ascertaining the relation between crystal structure and electronic property for the further analysis of its topological properties.
文摘通过优化照相机的内部参数,运用基于转轴法的外切矩形法对工件进行定位,确定工件像素级的姿态和尺寸;选取物体的ROI后,运用双线性差值算法,实现工件边缘的亚像素提取,通过黑塞范式直线拟合,找到精确的物体边缘;最终实现了运用500万像素的工业照相机,在全景拍摄条件下,测量尺寸在80-150 mm的工件,测量重复性精度可以达到0.015 mm.
