Electronic States and Mixing of Different Symmetry or Antiferromagnetism in Vortex Cores in dx2-y2-wave Superconductivity
Electronic States and Mixing of Different Symmetry or Antiferromagnetism in Vortex Cores in dx2-y2-wave Superconductivity
复制标题
dx2-y2波超导涡核中不同对称性或反铁磁性的电子态和混合
DOI：
10.1142/s0217979299003428
复制
发表时间：
1999
影响因子：
1.7
通讯作者：
M. Ogata
中科院分区：
文献类型：
--
作者：
M. Ogata
本文用二维t-J模型研究了高温超导体中涡旋的微观结构。利用Gutzwiller近似自洽地确定了序参量的空间依赖性，其中考虑了相关性的影响。在高掺杂区，对势具有dx ~ 2-y ~ 2波的性质，在芯附近的局域态密度出现零能峰。然而，在低掺杂区，空间振荡（扩展）s波型序参量是局部诱导周围的涡核。结果表明，核附近的局域态密度显示出零能峰的分裂。这为YBCO的扫描隧道谱实验数据提供了一种可能的解释。通过对Gutzwiller近似的修正，研究了反铁磁涡旋核的可能性。结果表明，在反铁磁有序态的边界附近，反铁磁关联在涡核内部发展，即使体态是纯d波态。在这种情况下，靠近核心的局域态密度没有零能量峰，而是显示出类似于能隙的特征，这可以在实验中观察到。最后发现了涡旋核电荷的符号随掺杂率的变化。
The microscopic structure of vortices in high-Tc superconductors is studied using the two-dimensional t-J model. The spatial dependences of order parameters are determined self-consistently using the Gutzwiller approximation, in which the effect of correlation is into account. In the high-doping region, the pair potential has dx2-y2-wave nature and the local density of states in the vicinity of the core shows a zero-energy peak. However, in the low-doping region, a spatially oscillating (extended) s-wave-type order parameter is locally induced around the vortex core. As a result, the local density of states near the core shows a splitting of the zero-energy peak. This gives a possible explanation for the experimental data of scanning tunneling spectroscopy for YBCO. The possibility of the antiferromagnetic vortex core is also studied by modifying the Gutzwiller approximation. It is found that, close to the boundary to the antiferromagnetically ordered state, the antiferromagnetic correlation develops inside the vortex core, even if the bulk state is the pure d-wave state. In this case the local density of states near the core does not have a zero-energy peak but instead shows a gap-like feature, which can be observed experimentally. Finally the sign change of the charge of the vortex core as a function of the doping rate is found.