欠掺杂高温超导体中的涡旋电荷结构相变

利用平均场t-t′-U-V-V_c模型，通过自洽求解Bogoliubov-de Gennes方程，研究了高温超导体中涡旋结构的相变.发现增大原位排斥势U，自旋密度波、电荷密度波以及d波序参量由棋盘结构转变为条纹结构.模型哈密顿量中引入合适强度的长程库仑势后，欠掺杂高温超导体样品中也可以出现二维或者棋盘结构，结果与文献报道的扫描隧道显微镜实验结果一致. 关键词： 高温超导 涡旋结构 长程库仑势

Transation of charged vortex structures in underdoped high-temperature superconductors

Vortex structures in high-temperature superconductors are studied by solving Bogoliubov-de Gennes equations based on a mean-field t-t′-U-V-V_c model. The results show that transition from checkerboard pattern to stripe structure for spin density wave, charge density wave, and d-wave orderings may occur by enhancing the strength of the on-site repulsion U. When a reasonable long-range Coulomb interaction is introduced into the model Hamiltonian, two-dimensional modulations or the checkerboard patterns may appear for the underdoped samples, which is consistent with the scanning-tunneling-microscopy experiments.